Next Article in Journal
The Effect of SGLT2 Inhibitor Dapagliflozin on Serum Levels of Apelin in T2DM Patients with Heart Failure
Next Article in Special Issue
Ivermectin Affects Neutrophil-Induced Inflammation through Inhibition of Hydroxylysine but Stimulation of Cathepsin G and Phenylalanine Secretion
Previous Article in Journal
Tendinopathies and Pain Sensitisation: A Meta-Analysis with Meta-Regression
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Biomedicines
Volume 10
Issue 7
10.3390/biomedicines10071750
biomedicines-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Interleukin-18 Binding Protein in Immune Regulation and Autoimmune Diseases

by
Seung Yong Park
1,
Yasmin Hisham
2,
Hyun Mu Shin
3,
Su Cheong Yeom
4 and
Soohyun Kim
1,2,*
1
College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea
2
Laboratory of Cytokine Immunology, Department of Biomedical Science and Technology, Konkuk University, Seoul 05029, Korea
3
System Immunology, Wide River Institute of Immunology, Collage of Medicine, Seoul National University, Hongcheon-gun 25159, Korea
4
Graduate School of International Agricultural Technology, Seoul National University, Pyeongchang 25354, Korea
*
Author to whom correspondence should be addressed.
Biomedicines 2022, 10(7), 1750; https://doi.org/10.3390/biomedicines10071750
Submission received: 23 May 2022 / Revised: 13 July 2022 / Accepted: 16 July 2022 / Published: 20 July 2022
(This article belongs to the Collection Feature Papers in Immunology and Immunotherapy)
Browse Figures
Review Reports Versions Notes

Abstract

:
Natural soluble antagonist and decoy receptor on the surface of the cell membrane are evolving as crucial immune system regulators as these molecules are capable of recognizing, binding, and neutralizing (so-called inhibitors) their targeted ligands. Eventually, these soluble antagonists and decoy receptors terminate signaling by prohibiting ligands from connecting to their receptors on the surface of cell membrane. Interleukin-18 binding protein (IL-18BP) participates in regulating both Th1 and Th2 cytokines. IL-18BP is a soluble neutralizing protein belonging to the immunoglobulin (Ig) superfamily as it harbors a single Ig domain. The Ig domain is essential for its binding to the IL-18 ligand and holds partial homology to the IL-1 receptor 2 (IL-1R2) known as a decoy receptor of IL-1α and IL-1β. IL-18BP was defined as a unique soluble IL-18BP that is distinct from IL-18Rα and IL-18Rβ chain. IL-18BP is encoded by a separated gene, contains 8 exons, and is located at chr.11 q13.4 within the human genome. In this review, we address the difference in the biological activity of IL-18BP isoforms, in the immunity balancing Th1 and Th2 immune response, its critical role in autoimmune diseases, as well as current clinical trials of recombinant IL-18BP (rIL-18BP) or equivalent.

1. Regulation of IL-18BP

Interleukin-18 (IL-18) was discovered in 1995 as a novel interferon-γ (IFNγ) inducing factor (IGIF), and later it was named IL-18 (also known as IL-1F4) due to the amino acid sequence homology with IL-1β as well as sharing the processing enzyme, caspase-1. Moreover, IL-18 induces IFNγ, including other proinflammatory cytokines in the immune response to pathogens or cell damage. These danger inducements contact cell surface through pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs), which in turn bind to the Toll-like receptors (TLR). Then, the activated TLRs trigger myeloid differentiation factor 88 (MyD88) and allow it to make a complex with the interleukin-1 receptor-associated kinase (IRAK) as well as TNF receptor-associated factor (TRAF). This signaling pathway results in oligomerization of inflammasome, and consequently, caspase-1 becomes activated. On the other hand, the translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) induces several proinflammatory cytokines, including pro-interleukin IL-18 (pro-IL-18). The activated caspase is proteolytically cleaved and activates pro-IL-18 to be released from the cell as its mature form; IL-18 (Figure 1, left panel). First, secreted IL-18 binds to the IL-18 receptor alpha chain (IL-18Rα), then recruits the IL-18 receptor beta chain (IL-18Rβ) to initiate the signaling pathway. IL-18 signaling cascades elicited the activation of mitogen-activated protein kinases (MAPKs) and NF-κB, which in turn led to IFNγ and numerous inflammatory gene expressions and enabled continuous loop activation, as the binding of IL-18 to its receptor acts as a downstream activation for NF-κB, (Figure 1, right panel) [1,2,3,4,5,6,7,8].
IL-18 binding protein (IL-18BP) is a natural soluble antagonist, and it binds to the IL-18 ligand with a high affinity. This high-affinity binding of IL-18BP sufficiently blocks the interaction of IL-18 with the IL-18Rα ligand-binding chain on the cell surface and eventually inhibits the IL-18 signaling pathway. Therefore, IL-18BP is considered a potent IL-18 inhibitor (Figure 1, on the top). Furthermore, the production of IFNγ induces IL-18BP to be present as a control role under the term of negative feedback (Figure 2, upper left panel), and IL-18BP is found to be expressed in various organs, such as the spleen, small intestine, stomach, colon, placenta, and lung [7,8,9,10,11,12,13]. This is not surprising, as IL-18 was first described as an IFNγ inducing factor (IGIF) [14], and increasing evidence showed that IL-18 induces IFNγ under various conditions [2,15,16,17]. Notably, IL-18BP was found extracellularly and in 20-folds higher than IL-18 level in healthy sera, which conveys its important regulatory maintenance function [7,18,19,20]. Given that IL-18BP is constitutively expressed from various organs/tissues and secreted into the blood in which it is not anchored on the cell membrane. IL-18BP lacks a transmembrane domain; therefore, it acts as a local as well as systemic IL-18 feedback regulation. As a result, it reduces IFNγ production, avoiding the harmful effect of prolonged inflammatory reactions (Figure 2, upper left panel).
Both IL-18 and IL-18BP occupied a location within chromosome 11 in human genomes. However, each has a distinct cytoband location, q23.1 and q13, respectively [21]. Additionally, the IL-18BP promoter was found to hold several response elements that are required for basal activity. Among them, one site of IFN regulatory factor 1 response element (IRF-E), one site of signal transducer and activator of transcription 1 (STAT1), and two sites of CCAAT-enhancer binding protein beta (CEBP-β), all play a significant role in direct IL-18BP activation in several cell types [12,22]. Based on the existence of these transcription factors, some reports discovered an unexpected expression for IL-18BP irrespective of the presence of IL-18, such as its association with IL-27 [23]. It was found that IL-27 induces the mRNA transcription level as well as the secretion of IL-18BP protein level in a dose-dependent manner. This was accomplished through IL-27-mediated STAT1 activation, which in turn binds to the Gamma-activated sequence (GAS) element within the promoter of IL-18BP, and thus regulates its expression.
Moreover, this transcriptional activation of the IL-18BP promoter regulates the IL-18BP expression by IFNγ and other different stimuli (Figure 2, right panel) [12,24,25]. Notably, the IL-18BP induction was enhanced specifically upon IFNγ, while the levels of the induction varied between monocytes and epithelial cells. These IFNγ induced IL-18BP variation levels were controlled epigenetically through CpG methylation on the promoter region. Therefore, they were diminished in monocytes as the promoter CpG was found to be methylated in contrast to unmethylated in epithelial cells (Figure 2, lower left panel) [26]. As a result, not only CpG methylation, but also other epigenetic modifications can draw the specificity of IL-18BP related to cell types, which is still waiting to be investigated.

2. Difference in the Biological Activity of IL-18BP Isoforms

Initially, IL-18BP was discovered in 1999 by the IL-18 ligand affinity chromatographic analysis while looking for a soluble form of IL-18 receptor-ligand binding chain using concentrated human urine as a source of body fluid proteins [7,18,19,20]. It was defined as a unique soluble protein that is distinct from IL-18Rα and IL-18Rβ chain. IL-18BP is encoded by a separated gene and contains 8 exons. The protein encoded by the IL-18BP gene translated into four isoforms in humans, which were produced through the alternative splicing process. These isoforms are IL-18BPa, IL-18BPb, IL-18BPc, and IL-18BPd and have a length of 194, 199, 115, and 163 amino acids, respectively as shown in Figure 3. As previously mentioned, IL-18BP is a soluble neutralizing protein belonging to the immunoglobulin (Ig) superfamily as it harbors a single Ig domain. The Ig domain is essential for its binding to the IL-18 ligand and holds partial homology to the IL-1 receptor 2 (IL-1R2), which is known as a decoy receptor of IL-1α and IL-1β. Among them, two isoforms were found to be active, IL-18BPa and IL-18BPc, since both hold the complete Ig domain. However, their binding affinities to the IL-18 are distinct. IL-18BPa showed an 18 times higher affinity to the IL-18 than IL-18BPc, this is predominantly due to the C-terminal difference. While, on the other hand, IL-18BPb and IL-18BPd lack the essential Ig domain, and thus show no activity in sequestering IL-18. As a result, no inhibition of the IL-18 signal pathway occur [4,5,6,7]. Furthermore, the sequence differences between isoforms point toward different post translational modifications (PTM). Although IL-18BP was reported as a heavily glycosylated protein, isoform b (O95998-3) showed missing conserved amino acids for PTMs. While the two closer isoforms, IL-18BPa and IL-18BPc (O95998, and G3V1C5), hold amino acids for all available PTMs, which are three sites for N-linked glycosylation, site for O-linked glycosylation, and the cysteines for two disulfide bridges, as shown in Figure 3. These modifications may play a key role in the activity of the respective protein/isoform, which also might acknowledge the less or no activity for isoforms other than IL-18BPa. In addition, the amino acid sequence of IL-37 was reported to have some similarity with IL-18 within the binding motif. Therefore, it was suggested that IL-37 might bind to IL-18 receptors and IL-18BP. Yet, these binding and their consequent effect still require additional investigation [27].

3. IL-18BP in Immunity Balancing between Th1 and Th2 Immune Response

The anti-inflammatory function of IL-18BP is linked to IL-18 inflammatory activity. Therefore, dysregulation in the balance between IL-18 and IL-18BP results in various disease conditions, which are mainly associated with immunity, an immune response against non-self-antibodies (pathogens), such as viruses, an immune reaction against self-antibodies (autoimmune reactions), and immunity toward cancers [28,29,30,31,32,33,34,35,36,37,38]. As the balance of IL-18 and IL-18BP is disrupted, the immune cell balances are also disrupted, for example, the balance of Th1 and Th2 as well as the balance of Th17 and Treg [28,29,39,40,41,42,43,44]. The balance between Th1 and Th2 immunity at homeostasis or change in this equilibrium due to an immune response to cope with a specific condition is highly regulated by the cellular environment, including levels and types of Th1 and Th2 cytokines [40,41,45]. Negative feedback is required to stop or avoid an overactivated immune response that may increase damage to adjacent healthy cells. IL-18BP is one of the most interesting contributors for the regulation of Th1 and Th2 immune responses (Figure 4) [2,7,28,43,46].
Moreover, as IL-18BP maintains its immune regulation through sequestering IL-18, the IL-18 subsequent activation will be inhibited under various conditions. IL-18 together with IL-12 is associated with immunity against foreign unknown antigens, such as harmful pathogens or pathogenesis of autoimmune diseases. The activated M1 macrophage stimulated Th1 T cells, which in turn induced NK cell activation, cytotoxic T cells, and IFNγ production [47,48,49,50,51,52]. IL-18BP substantially downregulates the production of Th1 cytokines, and thus regulates the balance between Th1 and Th2 responses [7,10].
Additionally, in the absence of IL-12, IL-18 can stimulate Th2 or Th17 response, depending on a costimulatory cytokine which combines with IL-18. For example, when IL-18 is combined with IL-2, they induce mucosal mast cytosis through elevating IL-3 and IL-9 cytokines [53]. Nonetheless, Th2 cytokines are found within allergic conditions and are characterized by increasing IgE production. IL-4 is the major Th2 cytokine, and when combined with IL-18, both induce M2 macrophage and Th2 cells activation resulting in an increase in the production of IgE and Th2 cytokines, for instance, IL-13 and IL-4 [28,54,55,56,57,58,59]. Moreover, IL-18 is suggested to induce an allergic inflammatory response even without IgE help, as is the case in basophils and mast cells activation upon IL-18 with IL-3 [3,57]. Therefore, IL-18BP has also a regulatory effect on Th2 immune response by inhibiting IL-18 activation cascades.

4. IL-18BP in Immunity Balancing between Th17 and Treg

Inflammasome-derived IL-18 promotes the production of Th17 cells, cells that induce inflammation, and thus reduce Treg cells, as well as cells that have an immunosuppressor function [60,61,62]. By contrast, when IL-18BP blocks IL-18, subsequently, the Th17 differentiation and Treg will eventually increase and disrupt the balance between Th17 and Treg. The inhibition of Th17 and elevation of Treg cells are beneficial when the superior immune reaction is unwanted, such as in the bone loss process. Additionally, in this case, IL-18BP has been suggested for use in treating osteoporosis [44,63]. Although viruses and cancer cells have granted the benefit of this inhibitory role of IL-18BP to increase Treg cells, and thus evade immune system recognition.
On the one hand, a small number of viruses, such as Poxviruses (C12L, D5L, EVM013, CPXV024), Yatapoxviruses (14L), and Molluscipoxvirus (MC053L, MC054L), encode at least one copy of IL-18BP homologs (named viral IL-18BP; vIL-18BP) [64,65,66,67,68,69,70]. The vIL-18BP was found to have similar human IL-18 binding sites [65], explaining the viral dissemination and modulation of the host antiviral response, which result in immune evasion. In addition to its ability to bind and neutralize IL-18, it was found to reduce IFNγ production in vitro studies [64,65,66,69,70,71]. Moreover, deleting vIL-18BP in these viruses potentially improves the respective live attenuated vaccines [72].
Moreover, mycobacterium tuberculosis (MTB), which caused tuberculosis (TB) pulmonary illness, has been known for its immune evasion, and thus still has serious clinical concerns. Lately, IL-18, as well as IL-18BP, has been found to be associated with active TB infection [73]. In this regard, IL-18 was identified as one of the pivotal cytokines that regulate macrophage cells during this infection in supplement with IL-12, IL-27, IFNγ, and TNFα [74]. Recently, serum levels of IL-18BP were shown as one of the potential biomarkers to discriminate between latent and active TB, further between active TB and non-mycobacterial community-acquired pneumonia (CAP) [73,75,76].
On the other hand, IL-18 is highly expressed in several cancers, within its microenvironment IL-18BP acts as a barrier for the cancer niche not only by increasing Treg, but also by attenuating natural killer (NK)-mediated killing [77,78,79]. In addition to the upregulation of IL-18BP in inflammatory conditions as mentioned earlier, IL-18BP is upregulated in various cancer types, such as breast [80], pancreas [33], prostate [31], and ovarian [34]. Therefore, IL-18BP has been suggested as an immunotherapy potential target for many cancers [77,81]. Initially, a clinical trial started with a recombinant IL-18 (rIL-18: SB-485232). However, during phase II, this recombinant cytokine demonstrated inadequate anti-tumor activity, especially with metastatic cancers. Therefore, it was further tested in combination with other therapies (ClinicalTrials.gov Identifier: NCT00107718) [82,83]. This unexpected lower efficiency is mostly due to the production of IL-18BP in the cancer microenvironment that neutralizes exogenous IL-18, as well. Recently, Zhou et al. have engineered an effective anti-tumor decoy-resistant IL-18 (DR-18). Namely, in contrast to the wild type rIL-18, it is characterized by the reinstate NK cell function, and thus promotes cancer clearance, suggesting the enhancement of anti-tumor immunity with other immunotherapies [78,79,84]. Still, further studies are needed to evaluate the newly developed DR-18 agonist for several cancer types. This finding encourages researchers and pharmaceutical companies to unveil more similar molecules that can effectively facilitate cancer clearance.
Nevertheless, it was shown that the absence of IL-18BP resulted in excessive IL-18 activity, which leads to strong and uncontrolled immune reactions, such as in the case of acute renal injury, cholestatic liver injury, and acute live injury [85,86,87,88]. In line with this fact, the loss of IL-18BP function seems to be fatal for humans, considering that in 2019 a case report confirmed the death of a child with a loss-of-function mutation in IL-18BP (homozygous 40-nucleotide deletion) upon hepatitis A virus infection [89]. As in this recently mentioned case, the infection was followed by an endless NK activation due to continuously released IL-18 without its sequestering by the loss of IL-18BP function causing cytotoxicity for healthy hepatic cells, thus disrupting immunity, and establishing toxicity and lethality. Therefore, the absence of IL-18BP reveals that the baseline levels of IL-18 can be destructive to humans, and thus it should be examined wisely and monitored continually.

5. IL-18BP in Autoimmune Diseases

IL-18/IL-18BP imbalance is highly linked to immunologically mediated diseases, especially diseases that have a pathological role of IFNγ, such as macrophage activated syndrome (MAS) [2,32,90,91,92,93,94]. MAS is a life-threatening condition that is not mainly a syndrome on its own, but is also found to be associated with other infectious and autoinflammatory diseases [2,32,93,95,96,97,98,99,100]. Various infections developed MAS, including Epstein–Barr virus, cytomegalovirus, and herpes virus, and infections with other pathogens, such as intracellular bacteria and parasites, as well as numerous lymphomas [32,90,91,92,93]. Moreover, MAS could be present as a form of secondary hemophagocytic lymphohistiocytosis (HLH), in addition to the rare and serious rheumatic diseases, such as adult-onset Still’s disease (AOSD) and its counterpart in children and systemic juvenile idiopathic arthritis (sJIA) [94,101,102,103,104,105]. In both conditions, secondary HLH and AOSD/sJIA, a significant elevation of IL-18 was validated and found to be correlated to disease activity and severity [94,104,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125]. MAS and IL-18 serum levels both represent the shared pathogenic features between these two different disease conditions. Under active MAS, IL-18 induces T cells expansion, and thus enhances the production of IFNγ and antigen-presenting cells (APCs) activation, predominantly dendritic cells (DCs), which in turn support the activation of macrophages. Consequently, this activation results in prolonged activation of these cells along with their inflammatory mediators, such as cytokine storm [106,107,108]. Therefore, increasing evidence showed that MAS-associated AOSD/sJIA had higher levels of IL-18 when compared to patients with no MAS association, IL-18BP or equivalent, which are suggested as a potential therapeutic option to neutralize IL-18 for MAS-associated conditions [95,120,126,127,128]. This suggestion was translated into drugs that are currently under distinct phases of clinical trials, which were summarized in Table 1.
Tadekinig-α is a human recombinant IL-18BP (rhIL-18BP) with an IL-18 high affinity and has been investigated in two serious inflammatory conditions that are associated with unusual elevation of IL-18 plasma levels; AOSD/sJIA and a refractory HLH bearing a gain of function mutation named NLR family CARD domain containing 4 (NLRC4)-related MAS. To date, promising results showed a favorable response toward Tadekinig-α in AOSD/sJIA and NLRC4-related MAS, which are currently under phase II and III, respectively (ClinicalTrials.gov Identifier: NCT02398435, NCT03113760, NCT03512314) [104,129,130,131]. Notably, in phase II clinical trial on Tadekinig-α, 50% of the AOSD cohort reached normal body temperature and reduced C-reactive protein (CRP) levels within 3 weeks under treatment, confirming the neutralization effect of the free bioactive IL-18 [129]. More recently, a case report revealed undetectable serum levels of the free IL-18 after only 2 h upon first administration of Tadekinig-α, while again increased when the administration of Tadekinig-α was discontinued [130].
MicroRNAs (miRNAs) are known as short non-coding sequences of RNA, which show a repression function. Notably, the reported miRNA (miRNA-134) that targeted IL-18BP, was found to be elevated in AOSD plasma and correlated with the activity of the disease [132]. It is well known that changes in miRNAs are considered as post-transcription gene regulators, and participate in human disorder pathogenesis [133]. Therefore, miRNA-134 can be an AOSD biomarker as well as a target for augmentation therapy. On the other hand, HLH patients carrying the NLRC4 mutation were examined under the Tadekinig-α regimen earlier than AOSD/sJIA, demonstrating a successful treatment in HLH holding NLRC4 genetic background [131,134,135].
Although IL-18/IL-18BP has significantly dysregulated in the abovementioned MAS-associated diseases, the imbalance of IL-18/IL-18BP has also been noticed in other inflammatory diseases, including rheumatoid arthritis (RA), psoriasis, asthma, lupus erythematosus, multiple sclerosis, atherosclerosis, renal and liver injury, inflammatory bowel disease (IBD), Crohn’s disease (CD), organ transplant rejection together with Graft versus host disease (GvHD), and most recently in pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome [15,37,86,136,137,138,139,140,141,142,143,144,145,146,147,148], where cytokine imbalance is a major feature of these autoimmune disorders. The refractory monogenic inflammatory disorder, PAPA, resulted from a dominant mutation with the proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1) gene and is characterized by acne and skin ulceration. In addition, the autoimmune neutrophilic destruction of joints and skin is the major clinical presentation of PAPA, but it was not associated with MAS [149,150]. Moreover, a recently published study found that IL-18 is elevated in the patient serum and this elevation was highly associated with the disease outcome, again with no MAS risk [148].
Therefore, IL-18 elevation and depletion in IL-18BP function is a biomarker for most of these diseases. However, targeting IL-18 by IL-18BP or equivalent is yet to be fully explored. Humanized IgG1 monoclonal antibody (anti-IL-18), GSK1070806, is instantly in the development phase for treating a variety of inflammatory conditions, atopic dermatitis (AD) and IBD in phase I, delayed graft function, CD, and Behcet’s disease in phase II (ClinicalTrials.gov Identifier: NCT04975438, NCT01035645, NCT02723786, NCT03681067, NCT03522662) [151]. In addition to Tadekinig-α and GSK1070806, a long-acting antibody drug targeting IL-18 and APB-R3 is developed for inflammatory autoimmune disease treatment in preclinical stages, and will soon enter phase I clinical trial [152].
Improving IL-18 targeting by allowing it to act for a longer time or with superior affinity appears to be promising and beneficial, taking into consideration sequence and structural features that affect the binding interaction. A recent structural study aimed to characterize the IL-18BP sequestration mechanism and reveal a novel disulfide-linked boundary, resulting in tetrameric assembly between IL-18BP and IL-18 [153]. During their study, due to N-terminal heavy glycosylation, they produce hIL-18BPΔN, an hIL-18BP that lacks N-terminal residues 63-194 and is treated with Endoglycosidase H. This form has lower glycosylation and still has the disulfide bridge, which shows a comparable IL-18 sequestering ability with high affinity, but at a higher rate. Therefore, hIL-18BPΔN might be a promising IL-18 neutralizing drug (see Figure 3 and Figure 4).
IL-18 has been involved in the injury of several organs as well as in potentially fatal conditions, which are exemplified by a cytokine storm. Lately, after the emergence of the COVID-19 crisis, heavy-handed cases of SARS CoV-2 infection showed a cytokine storm that derives tissue damage [154,155,156,157]. The COVID-19 mediated cytokine storm showed that elevated IL-18 is one of the cytokines involved in the storm. Moreover, due to its remarkable elevation, IL-18 was recognized as a biomarker for disease severity [154,155,157,158,159]. Therefore, IL-18BP has been suggested as a promising therapy for COVID-19. Yet, there are no pre or clinical trials in this regard [17,160,161]. Furthermore, the lack of proper and well-characterized animal models slows down the movement for further discovering and understanding IL-18BP as a potential therapeutic option for a wide range of disorders.

Author Contributions

Conceptualization, S.Y.P., Y.H., H.M.S., S.C.Y., and S.K.; supervision, S.K.; funding acquisition, S.Y.P. and S.K.; writing—original draft, S.Y.P., Y.H., and S.K.; writing—review and editing, S.Y.P. and S.K. All authors have read and agreed to the published version of the manuscript.

Funding

This paper was written as part of Konkuk University’s research support program for its faculty on sabbatical leave in 2013. This work was supported by the National Research Foundation of Korea (NRF-2021R1F1A1057397). This research was supported by the Main Research Program (E0210602-02) of the Korea Food Research Institute (KFRI) funded by the Ministry of Science and ICT.

Conflicts of Interest

The authors declare no conflict of interest.

Abbreviations

ADAtopic dermatitis
AOSDAdult-onset Still’s disease
APCsAntigen-presenting cells
CAPCommunity-acquired pneumonia
CDCrohn’s disease
CEBP-βCCAAT-enhancer binding protein beta
COVID-19Coronavirus disease 2019
CRPC-reactive protein
DAMPsdamage-associated molecular patterns
DCsDendritic cells
GASGamma-activated sequence
GvHDGraft versus host disease
HLHhemophagocytic lymphohistiocytosis
IgImmunoglobulin
IBDInflammatory bowel disease
IFNInterferon
IFNγR1IFNγ receptor 1
IFNγR2IFNγ receptor 2
IRAKinterleukin-1 receptor-associated kinase
IRFsInterferon regulatory factors
IRF-EIFN regulatory factor 1 response element
ILInterleukin
IL-1RIL-1 receptor
IL-18BPIL-18 binding protein
IL-18RαIL-18 receptor alpha chain
IL-18RβIL-18 receptor beta chain
JAKJanus kinase
MASMacrophage activated syndrome
miRNAsMicroRNAs
MTBMycobacterium tuberculosis
NF-κBNuclear factor kappa-light-chain-enhancer of activated B cells
NKNatural killer
NLRC4NLR family CARD domain containing 4
PAMPsPathogen-associated molecular patterns
PAPAPyoderma gangrenosum and acne
Pro-IL-18pro-interleukin IL-18
PRRsPattern recognition receptors
PTMPost translational modifications
RARheumatoid arthritis
SARS CoV-2Severe acute respiratory syndrome coronavirus 2
STAT1signal transducer and activator of transcription 1
TBTuberculosis
TLRToll-like receptors
TRAFTNF receptor associated factor
vIL-18BPviral IL-18BP

References

  1. Okamura, H.; Nagata, K.; Komatsu, T.; Tanimoto, T.; Nukata, Y.; Tanabe, F.; Akita, K.; Torigoe, K.; Okura, T.; Fukuda, S. A novel costimulatory factor for gamma interferon induction found in the livers of mice causes endotoxic shock. Infect. Immun. 1995, 63, 3966–3972. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  2. Dinarello, C.A.; Novick, D.; Kim, S.; Kaplanski, G. Interleukin-18 and IL-18 Binding Protein. Front. Immunol. 2013, 4, 289. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  3. Yasuda, K.; Nakanishi, K.; Tsutsui, H. Interleukin-18 in Health and Disease. Int. J. Mol. Sci. 2019, 20, 649. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  4. Halim, A.; Nilsson, J.; Rüetschi, U.; Hesse, C.; Larson, G. Human urinary glycoproteomics; attachment site specific analysis of N-and O-linked glycosylations by CID and ECD. Mol. Cell. Proteom. 2012, 11, M111.013649. [Google Scholar] [CrossRef] [Green Version]
  5. Kim, S.-H.; Eisenstein, M.; Reznikov, L.; Fantuzzi, G.; Novick, D.; Rubinstein, M.; Dinarello, C.A. Structural requirements of six naturally occurring isoforms of the IL-18 binding protein to inhibit IL-18. Proc. Natl. Acad. Sci. USA 2000, 97, 1190–1195. [Google Scholar] [CrossRef] [Green Version]
  6. Kaplanski, G. Interleukin-18: Biological properties and role in disease pathogenesis. Immunol. Rev. 2018, 281, 138–153. [Google Scholar] [CrossRef] [Green Version]
  7. Novick, D.; Kim, S.-H.; Fantuzzi, G.; Reznikov, L.L.; Dinarello, C.A.; Rubinstein, M. Interleukin-18 Binding Protein: A Novel Modulator of the Th1 Cytokine Response. Immunity 1999, 10, 127–136. [Google Scholar] [CrossRef] [Green Version]
  8. Aizawa, Y.; Akita, K.; Taniai, M.; Torigoe, K.; Mori, T.; Nishida, Y.; Ushio, S.; Nukada, Y.; Tanimoto, T.; Ikegami, H.; et al. Cloning and expression of interleukin-18 binding protein. FEBS Lett. 1999, 445, 338–342. [Google Scholar] [CrossRef] [Green Version]
  9. Im, S.-H.; Kim, S.-H.; Azam, T.; Venkatesh, N.; Dinarello, C.A.; Fuchs, S.; Souroujon, M.C. Rat Interleukin-18 Binding Protein: Cloning, Expression, and Characterization. J. Interf. Cytokine Res. 2002, 22, 321–328. [Google Scholar] [CrossRef]
  10. Paulukat, J.; Bosmann, M.; Nold, M.; Garkisch, S.; Kämpfer, H.; Frank, S.; Raedle, J.; Zeuzem, S.; Pfeilschifter, J.; Mühl, H. Expression and release of IL-18 binding protein in response to IFN-γ. J. Immunol. 2001, 167, 7038–7043. [Google Scholar] [CrossRef] [Green Version]
  11. Veenstra, K.G.; Jonak, Z.L.; Trulli, S.; Gollob, J.A. IL-12 induces monocyte IL-18 binding protein expression via IFN-γ. J. Immunol. 2002, 168, 2282–2287. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  12. Hurgin, V.; Novick, D.; Rubinstein, M. The promoter of IL-18 binding protein: Activation by an IFN-γ-induced complex of IFN regulatory factor 1 and CCAAT/enhancer binding protein β. Proc. Natl. Acad. Sci. USA 2002, 99, 16957–16962. [Google Scholar] [CrossRef] [Green Version]
  13. Möller, B.; Paulukat, J.; Nold, M.; Behrens, M.; Kukoc-Zivojnov, N.; Kaltwasser, J.P.; Pfeilschifter, J.; Mühl, H. Interferon-gamma induces expression of interleukin-18 binding protein in fibroblast-like synoviocytes. Rheumatology 2003, 42, 442–445. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  14. Nakamura, K.; Okamura, H.; Wada, M.; Nagata, K.; Tamura, T. Endotoxin-induced serum factor that stimulates gamma interferon production. Infect. Immun. 1989, 57, 590–595. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  15. Esmailbeig, M.; Ghaderi, A. Interleukin-18: A regulator of cancer and autoimmune diseases. Eur. Cytokine Netw. 2017, 28, 127–140. [Google Scholar] [CrossRef] [PubMed]
  16. Fu, C.; Chen, J.; Lu, J.; Yi, L.; Tong, X.; Kang, L.; Pei, S.; Ouyang, Y.; Jiang, L.; Ding, Y.; et al. Roles of inflammation factors in melanogenesis. Mol. Med. Rep. 2020, 21, 1421–1430. [Google Scholar] [CrossRef] [Green Version]
  17. Vecchié, A.; Bonaventura, A.; Toldo, S.; Dagna, L.; Dinarello, C.A.; Abbate, A. IL-18 and infections: Is there a role for targeted therapies? J. Cell. Physiol. 2021, 236, 1638–1657. [Google Scholar] [CrossRef]
  18. Novick, D.; Schwartsburd, B.; Pinkus, R.; Suissa, D.; Belzer, I.; Sthoeger, Z.; Keane, W.F.; Chvatchko, Y.; Kim, S.-H.; Fantuzzi, G.; et al. A novel IL-18BP ELISA shows elevated serum IL-18BP in sepsis and extensive decrease of free IL-18. Cytokine 2001, 14, 334–342. [Google Scholar] [CrossRef] [Green Version]
  19. Principe, S.; Jones, E.E.; Kim, Y.; Sinha, A.; Nyalwidhe, J.O.; Brooks, J.; Semmes, O.J.; Troyer, D.A.; Lance, R.S.; Kislinger, T.; et al. In-depth proteomic analyses of exosomes isolated from expressed prostatic secretions in urine. Proteomics 2013, 13, 1667–1671. [Google Scholar] [CrossRef] [Green Version]
  20. Sonek, J.; Blumenfeld, M.; Foley, M.; Johnson, F.; Iams, J. Cervical length may change during ultrasonographic examination. Am. J. Obstet. Gynecol. 1990, 62, 1355–1357. [Google Scholar] [CrossRef]
  21. Taylor, T.D.; Noguchi, H.; Totoki, Y.; Toyoda, A.; Kuroki, Y.; Dewar, K.; Lloyd, C.; Itoh, T.; Takeda, T.; Kim, D.-W.; et al. Human chromosome 11 DNA sequence and analysis including novel gene identification. Nature 2006, 440, 497–500. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  22. Murray, D.R.; Mummidi, S.; Valente, A.J.; Yoshida, T.; Somanna, N.K.; Delafontaine, P.; Dinarello, C.A.; Chandrasekar, B. β2 adrenergic activation induces the expression of IL-18 binding protein, a potent inhibitor of isoproterenol induced cardiomyocyte hypertrophy in vitro and myocardial hypertrophy in vivo. J. Mol. Cell. Cardiol. 2012, 52, 206–218. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  23. Wittmann, M.; Doble, R.; Bachmann, M.; Pfeilschifter, J.; Werfel, T.; Mühl, H. IL-27 Regulates IL-18 Binding Protein in Skin Resident Cells. PLoS ONE 2012, 7, e38751. [Google Scholar] [CrossRef] [PubMed]
  24. Bachmann, M.; Paulukat, J.; Pfeilschifter, J.; Mühl, H. Molecular mechanisms of IL-18BP regulation in DLD-1 cells: Pivotal direct action of the STAT1/GAS axis on the promoter level. J. Cell. Mol. Med. 2009, 13, 1987–1994. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  25. Liu, X.; Yang, H.; Liu, Y.; Jiao, Y.; Yang, L.; Wang, X.; Yu, W.; Su, D.; Tian, J. Remifentanil upregulates hepatic IL-18 binding protein (IL-18BP) expression through transcriptional control. Lab. Investig. 2018, 98, 1588–1599. [Google Scholar] [CrossRef] [PubMed]
  26. Bachmann, M.; Pfeilschifter, J.; Muhl, H. Epigenetic regulation by CpG methylation splits strong from retarded IFNgamma-induced IL-18BP in epithelial versus monocytic cells. Biochim. Biophys. Acta (BBA)—Gene Regul. Mech. 2018, 1861, 191–199. [Google Scholar] [CrossRef] [PubMed]
  27. Yang, Y.; Zhang, Z.-X.; Lian, D.; Haig, A.; Bhattacharjee, R.N.; Jevnikar, A.M. IL-37 inhibits IL-18-induced tubular epithelial cell expression of pro-inflammatory cytokines and renal ischemia-reperfusion injury. Kidney Int. 2015, 87, 396–408. [Google Scholar] [CrossRef] [Green Version]
  28. Leng, J.; Yao, H.; Shen, J.; Wang, K.; Zhuo, G.; Wang, Z. Co-expression of IL-18 binding protein and IL-4 regulates Th1/Th2 cytokine response in murine collagen-induced arthritis. Acta Biochim. Biophys. Sin. 2008, 40, 116–124. [Google Scholar] [CrossRef] [Green Version]
  29. Chirathaworn, C.; Rianthavorn, P.; Wuttirattanakowit, N.; Poovorawan, Y. Serum IL-18 and IL-18BP Levels in Patients with Chikungunya Virus Infection. Viral Immunol. 2010, 23, 113–117. [Google Scholar] [CrossRef]
  30. Iannello, A.; Boulassel, M.; Samarani, S.; Tremblay, C.; Toma, E.; Routy, J.; Ahmad, A. HIV-1 Causes an Imbalance in the Production of Interleukin-18 and Its Natural Antagonist in HIV-Infected Individuals: Implications for Enhanced Viral Replication. J. Infect. Dis. 2010, 201, 608–617. [Google Scholar] [CrossRef]
  31. Fujita, K.; Ewing, C.M.; Isaacs, W.B.; Pavlovich, C.P. Immunomodulatory IL-18 binding protein is produced by prostate cancer cells and its levels in urine and serum correlate with tumor status. Int. J. Cancer 2011, 129, 424–432. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  32. Mazodier, K.; Marin, V.; Novick, D.; Farnarier, C.; Robitail, S.; Schleinitz, N.; Veit, V.; Paul, P.; Rubinstein, M.; Dinarello, C.A.; et al. Severe imbalance of IL-18/IL-18BP in patients with secondary hemophagocytic syndrome. Blood 2005, 106, 3483–3489. [Google Scholar] [CrossRef] [PubMed]
  33. Carbone, A.; Vizio, B.; Novarino, A.; Mauri, F.A.; Geuna, M.; Robino, C.; Brondino, G.; Prati, A.; Giacobino, A.; Campra, D.; et al. IL-18 Paradox in Pancreatic Carcinoma: Elevated Serum Levels of Free IL-18 are Correlated With Poor Survival. J. Immunother. 2009, 32, 920–931. [Google Scholar] [CrossRef] [PubMed]
  34. Carbotti, G.; Barisione, G.; Orengo, A.M.; Brizzolara, A.; Airoldi, I.; Bagnoli, M.; Pinciroli, P.; Mezzanzanica, D.; Centurioni, M.G.; Fabbi, M.; et al. The IL-18 antagonist IL-18-binding protein is produced in the human ovarian cancer microenvironment. Clin. Cancer Res. 2013, 19, 4611–4620. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  35. Shao, Q.; Liu, N.; Li, G.-F.; Meng, Q.-C.; Yao, J.-H.; Wang, N. IL-18 expression in clinical human pituitary adenoma. Technol. Health Care 2022, 30, 11–16. [Google Scholar] [CrossRef]
  36. Kaur, D.; Chachi, L.; Gomez, E.; Sylvius, N.; Brightling, C.E. Interleukin-18, IL-18 binding protein and IL-18 receptor expression in asthma: A hypothesis showing IL-18 promotes epithelial cell differentiation. Clin. Transl. Immunol. 2021, 10, e1301. [Google Scholar] [CrossRef]
  37. Hirooka, Y.; Nozaki, Y. Interleukin-18 in Inflammatory Kidney Disease. Front. Med. 2021, 8, 639103. [Google Scholar] [CrossRef]
  38. Liang, R.; Zheng, L.; Ji, T.; Zheng, J.; Liu, J.; Yuan, C.; Huang, Q.; Yang, M. Elevated serum free IL-18 in neuropsychiatric systemic lupus erythematosus patients with seizure disorders. Lupus 2022, 31, 187–193. [Google Scholar] [CrossRef]
  39. Nakanishi, K.; Yoshimoto, T.; Tsutsui, H.; Okamura, H. Interleukin-18 Regulates Both Th1 and Th2 Responses. Annu. Rev. Immunol. 2001, 19, 423–474. [Google Scholar] [CrossRef]
  40. Abbas, A.K.; Murphy, K.M.; Sher, A. Functional diversity of helper T lymphocytes. Nature 1996, 383, 787–793. [Google Scholar] [CrossRef]
  41. Kamradt, T.; Burmester, G.R. Cytokines and arthritis: Is the Th1/Th2 paradigm useful for understanding pathogenesis? J. Rheumatol. 1998, 25, 6–8. [Google Scholar]
  42. Shan, N.N.; Ji, X.B.; Wang, X.; Li, Y.; Liu, X.; Zhu, X.J.; Hou, M. In vitro recovery of Th1/Th2 balance in PBMCs from patients with immune thrombocytopenia through the actions of IL-18BPa/Fc. Thromb. Res. 2011, 128, e119–e124. [Google Scholar] [CrossRef]
  43. Novick, D.; Kim, S.; Kaplanski, G.; Dinarello, C.A. Interleukin-18, more than a Th1 cytokine. Semin. Immunol. 2013, 25, 439–448. [Google Scholar] [CrossRef] [PubMed]
  44. Min, H.K.; Kim, S.; Lee, J.-Y.; Kim, K.-W.; Lee, S.-H.; Kim, H.-R. IL-18 binding protein suppresses IL-17-induced osteoclastogenesis and rectifies type 17 helper T cell / regulatory T cell imbalance in rheumatoid arthritis. J. Transl. Med. 2021, 19, 392. [Google Scholar] [CrossRef] [PubMed]
  45. Kidd, P. Th1/Th2 balance: The hypothesis, its limitations, and implications for health and disease. Altern. Med. Rev. 2003, 8, 223–246. [Google Scholar]
  46. Nakanishi, K.; Yoshimoto, T.; Tsutsui, H.; Okamura, H. Interleukin-18 is a unique cytokine that stimulates both Th1 and Th2 responses depending on its cytokine milieu. Cytokine Growth Factor Rev. 2001, 12, 53–72. [Google Scholar] [CrossRef]
  47. Nakamura, K.; Okamura, H.; Nagata, K.; Komatsu, T.; Tamura, T. Purification of a factor which provides a costimulatory signal for gamma interferon production. Infect. Immun. 1993, 61, 64–70. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  48. Fehniger, T.A.; Shah, M.H.; Turner, M.J.; VanDeusen, J.B.; Whitman, S.P.; Cooper, M.A.; Suzuki, K.; Wechser, M.; Goodsaid, F.; Caligiuri, M.A. Differential cytokine and chemokine gene expression by human NK cells following activation with IL-18 or IL-15 in combination with IL-12: Implications for the innate immune response. J. Immunol. 1999, 162, 4511–4520. [Google Scholar]
  49. Munder, M.; Mallo, M.; Eichmann, K.; Modolell, M. Murine macrophages secrete interferon γ upon combined stimulation with interleukin (IL)-12 and IL-18: A novel pathway of autocrine macrophage activation. J. Exp. Med. 1998, 187, 2103–2108. [Google Scholar] [CrossRef] [Green Version]
  50. Tsutsui, H.; Nakanishi, K.; Matsui, K.; Higashino, K.; Okamura, H.; Miyazawa, Y.; Kaneda, K. IFN-gamma-inducing factor up-regulates Fas ligand-mediated cytotoxic activity of murine natural killer cell clones. J. Immunol. 1996, 157, 3967–3973. [Google Scholar]
  51. Dinarello, C.A. IL-18: A TH1 -inducing, proinflammatory cytokine and new member of the IL-1 family. J. Allergy Clin. Immunol. 1999, 103, 11–24. [Google Scholar] [CrossRef]
  52. Swain, S.L. Interleukin 18: Tipping the balance towards a T helper cell 1 response. J. Exp. Med. 2001, 194, F11–F14. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  53. Sasaki, Y.; Yoshimoto, T.; Maruyama, H.; Tegoshi, T.; Ohta, N.; Arizono, N.; Nakanishi, K. IL-18 with IL-2 protects against Strongyloides venezuelensis infection by activating mucosal mast cell–dependent type 2 innate immunity. J. Exp. Med. 2005, 202, 607–616. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  54. Tanaka, H.; Miyazaki, N.; Oashi, K.; Teramoto, S.; Shiratori, M.; Hashimoto, M.; Ohmichi, M.; Abe, S. IL-18 might reflect disease activity in mild and moderate asthma exacerbation. J. Allergy Clin. Immunol. 2001, 107, 331–336. [Google Scholar] [CrossRef]
  55. Hoshino, T.; Wiltrout, R.H.; A Young, H. IL-18 is a potent coinducer of IL-13 in NK and T cells: A new potential role for IL-18 in modulating the immune response. J. Immunol. 1999, 162, 5070–5077. [Google Scholar]
  56. Yoshimoto, T.; Mizutani, H.; Tsutsui, H.; Noben-Trauth, N.; Yamanaka, K.-I.; Tanaka, M.; Izumi, S.; Okamura, H.; Paul, W.E.; Nakanishi, K. IL-18 induction of IgE: Dependence on CD4+ T cells, IL-4 and STAT6. Nat. Immunol. 2000, 1, 132–137. [Google Scholar] [CrossRef]
  57. Yoshimoto, T.; Tsutsui, H.; Tominaga, K.; Hoshino, K.; Okamura, H.; Akira, S.; Akira, S.; Paul, W.E.; Nakanishi, K. IL-18, although antiallergic when administered with IL-12, stimulates IL-4 and histamine release by basophils. Proc. Natl. Acad. Sci. USA 1999, 96, 13962–13966. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  58. Sawada, M.; Kawayama, T.; Imaoka, H.; Sakazaki, Y.; Oda, H.; Takenaka, S.-I.; Kaku, Y.; Azuma, K.; Tajiri, M.; Edakuni, N.; et al. IL-18 Induces Airway Hyperresponsiveness and Pulmonary Inflammation via CD4+ T Cell and IL-13. PLoS ONE 2013, 8, e54623. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  59. Oda, H.; Kawayama, T.; Imaoka, H.; Sakazaki, Y.; Kaku, Y.; Okamoto, M.; Kitasato, Y.; Edakuni, N.; Takenaka, S.-I.; Yoshida, M.; et al. Interleukin-18 expression, CD8+ T cells, and eosinophils in lungs of nonsmokers with fatal asthma. Ann. Allergy Asthma Immunol. 2014, 112, 23–28.e1. [Google Scholar] [CrossRef] [PubMed]
  60. Conforti-Andreoni, C.; Spreafico, R.; Qian, H.L.; Riteau, N.; Ryffel, B.; Ricciardi-Castagnoli, P.; Mortellaro, A. Uric Acid-Driven Th17 Differentiation Requires Inflammasome-Derived IL-1 and IL-18. J. Immunol. 2011, 187, 5842–5850. [Google Scholar] [CrossRef] [Green Version]
  61. Mills, K.H.G.; Dungan, L.S.; Jones, S.A.; Harris, J. The role of inflammasome-derived IL-1 in driving IL-17 responses. J. Leukoc. Biol. 2013, 93, 489–497. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  62. Chen, J.M.; Li, Q.W.; Jiang, G.X.; Liu, J.S.; Cheng, Q. IL-18 induced IL-23/IL-17 expression impairs Abeta clearance in cultured THP-1 and BV2 cells. Cytokine 2019, 119, 113–118. [Google Scholar] [CrossRef] [PubMed]
  63. Mansoori, M.N.; Shukla, P.; Kakaji, M.; Tyagi, A.M.; Srivastava, K.; Shukla, M.; Dixit, M.; Kureel, J.; Gupta, S.; Singh, D. IL-18BP is decreased in osteoporotic women: Prevents Inflammasome mediated IL-18 activation and reduces Th17 differentiation. Sci. Rep. 2016, 6, 33680. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  64. Born, T.L.; Morrison, L.A.; Esteban, D.J.; Vandenbos, T.; Thebeau, L.G.; Chen, N.; Spriggs, M.K.; Sims, J.; Buller, R.M.L. A Poxvirus Protein That Binds to and Inactivates IL-18, and Inhibits NK Cell Response. J. Immunol. 2000, 164, 3246–3254. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  65. Reading, P.C.; Smith, G.L. Vaccinia Virus Interleukin-18-Binding Protein Promotes Virulence by Reducing Gamma Interferon Production and Natural Killer and T-Cell Activity. J. Virol. 2003, 77, 9960–9968. [Google Scholar] [CrossRef] [Green Version]
  66. Smith, V.P.; Bryant, N.A.; Alcamı, A. Ectromelia, vaccinia and cowpox viruses encode secreted interleukin-18-binding proteins. J. Gen. Virol. 2000, 81, 1223–1230. [Google Scholar] [CrossRef]
  67. Meng, X.; Leman, M.; Xiang, Y. Variola virus IL-18 binding protein interacts with three human IL-18 residues that are part of a binding site for human IL-18 receptor alpha subunit. Virology 2007, 358, 211–220. [Google Scholar] [CrossRef] [Green Version]
  68. Krumm, B.; Meng, X.; Wang, Z.; Xiang, Y.; Deng, J. A Unique Bivalent Binding and Inhibition Mechanism by the Yatapoxvirus Interleukin 18 Binding Protein. PLoS Pathog. 2012, 8, e1002876. [Google Scholar] [CrossRef]
  69. Nazarian, S.H.; Rahman, M.M.; Werden, S.J.; Villeneuve, D.; Meng, X.; Brunetti, C.; Valeriano, C.; Wong, C.; Singh, R.; Barrett, J.W.; et al. Yaba Monkey Tumor Virus Encodes a Functional Inhibitor of Interleukin-18. J. Virol. 2008, 82, 522–528. [Google Scholar] [CrossRef] [Green Version]
  70. Xiang, Y.; Moss, B. IL-18 binding and inhibition of interferon γ induction by human poxvirus-encoded proteins. Proc. Natl. Acad. Sci. USA 1999, 96, 11537–11542. [Google Scholar] [CrossRef] [Green Version]
  71. Xiang, Y.; Moss, B. Molluscum Contagiosum Virus Interleukin-18 (IL-18) Binding Protein Is Secreted as a Full-Length Form That Binds Cell Surface Glycosaminoglycans through the C-Terminal Tail and a Furin-Cleaved Form with Only the IL-18 Binding Domain. J. Virol. 2003, 77, 2623–2630. [Google Scholar] [CrossRef] [Green Version]
  72. Falivene, J.; Zajac, M.P.D.M.; Pascutti, M.F.; Rodriguez, A.M.; Maeto, C.; Perdiguero, B.; Gomez, C.E.; Esteban, M.; Calamante, G.; Gherardi, M.M. Improving the MVA Vaccine Potential by Deleting the Viral Gene Coding for the IL-18 Binding Protein. PLoS ONE 2012, 7, e32220. [Google Scholar] [CrossRef] [Green Version]
  73. Wawrocki, S.; Seweryn, M.; Kielnierowski, G.; Rudnicka, W.; Wlodarczyk, M.; Druszczynska, M. IL-18/IL-37/IP-10 signalling complex as a potential biomarker for discriminating active and latent TB. PLoS ONE 2019, 14, e0225556. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  74. Robinson, M.C.; Jung, J.Y.; Nau, G.J. Interferon-gamma, tumor necrosis factor, and interleukin-18 cooperate to control growth of Mycobacterium tuberculosis in human macrophages. Cytokine 2012, 60, 233–241. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  75. Wawrocki, S.; Seweryn, M.; Kielnierowski, G.; Rudnicka, W.; Druszczynska, M. IL-18 and related function proteins associated with tuberculosis severity and screening for active TB among patients with non-mycobacterial community-acquired pneumonia (CAP). Saudi J. Biol. Sci. 2020, 27, 3035–3045. [Google Scholar] [CrossRef]
  76. Wawrocki, S.; Kielnierowski, G.; Rudnicka, W.; Seweryn, M.; Druszczynska, M. Interleukin-18, functional IL-18 receptor and IL-18 binding protein expression in active and latent tuberculosis. Pathogens 2020, 9, 451. [Google Scholar] [CrossRef] [PubMed]
  77. Fabbi, M.; Carbotti, G.; Ferrini, S. Context-dependent role of IL-18 in cancer biology and counter-regulation by IL-18BP. J. Leukoc. Biol. 2015, 97, 665–675. [Google Scholar] [CrossRef] [PubMed]
  78. Dixon, K.O.; Kuchroo, V.K. IL-18: Throwing off the shackles to boost anti-tumor immunity. Cell Res. 2020, 30, 831–832. [Google Scholar] [CrossRef]
  79. Nakamura, K.; Bald, T.; Smyth, M.J. Cancer-killing, decoy-resistant interleukin-18. Immunol. Cell Biol. 2020, 98, 434–436. [Google Scholar] [CrossRef]
  80. Abrahamsson, A.; Rzepecka, A.; Dabrosin, C. Equal Pro-inflammatory Profiles of CCLs, CXCLs, and Matrix Metalloproteinases in the Extracellular Microenvironment In Vivo in Human Dense Breast Tissue and Breast Cancer. Front. Immunol. 2017, 8, 1994. [Google Scholar] [CrossRef] [Green Version]
  81. Muhl, H.; Bachmann, M. IL-18/IL-18BP and IL-22/IL-22BP: Two interrelated couples with therapeutic potential. Cell. Signal. 2019, 63, 109388. [Google Scholar] [CrossRef] [PubMed]
  82. Tarhini, A.A.; Millward, M.; Mainwaring, P.; Kefford, R.; Logan, T.; Pavlick, A.; Kathman, S.J.; Laubscher, K.H.; Dar, M.M.; Kirkwood, J.M. A phase 2, randomized study of SB-485232, rhIL-18, in patients with previously untreated metastatic melanoma. Cancer 2009, 115, 859–868. [Google Scholar] [CrossRef] [PubMed]
  83. Simpkins, F.; Flores, A.; Chu, C.; Berek, J.S.; Lucci, J.; Murray, S.; Bauman, J.; Struemper, H.; Germaschewski, F.; Jonak, Z.; et al. Chemoimmunotherapy Using Pegylated Liposomal Doxorubicin and Interleukin-18 in Recurrent Ovarian Cancer: A Phase I Dose-Escalation StudyIL-18 Plus PLD in Ovarian Cancer. Cancer Immunol. Res. 2013, 1, 168–178. [Google Scholar] [CrossRef] [Green Version]
  84. Zhou, T.; Damsky, W.; Weizman, O.-E.; McGeary, M.K.; Hartmann, K.P.; Rosen, C.E.; Fischer, S.; Jackson, R.; Flavell, R.A.; Wang, J.; et al. IL-18BP is a secreted immune checkpoint and barrier to IL-18 immunotherapy. Nature 2020, 583, 609–614. [Google Scholar] [CrossRef] [PubMed]
  85. Tong, C.; Li, J.; Lin, W.; Cen, W.; Zhang, W.; Zhu, Z.; Lu, B.; Yu, J. Inhibition of heat shock protein 90 alleviates cholestatic liver injury by decreasing IL-1beta and IL-18 expression. Exp. Ther. Med. 2021, 21, 241. [Google Scholar] [CrossRef]
  86. Dokumacioğlu, E.; Iskender, H.; Kapakin KA, T.; Yenice, G.; Mokthare, B.; Bolat, I.; Hayirli, A. Effect of betulinic acid administration on TLR-9/NF-ΚB/IL-18 levels in experimentalliver injury. Turk. J. Med. Sci. 2021, 51, 1544–1553. [Google Scholar] [CrossRef]
  87. Endre, Z.H.; Westhuyzen, J. Early detection of acute kidney injury: Emerging new biomarkers (Review Article). Nephrology 2008, 13, 91–98. [Google Scholar] [CrossRef]
  88. Washburn, K.K.; Zappitelli, M.; Arikan, A.A.; Loftis, L.; Yalavarthy, R.; Parikh, C.R.; Edelstein, C.L.; Goldstein, S.L. Urinary interleukin-18 is an acute kidney injury biomarker in critically ill children. Nephrol. Dial. Transplant. 2008, 23, 566–572. [Google Scholar] [CrossRef] [Green Version]
  89. Belkaya, S.; Michailidis, E.; Korol, C.B.; Kabbani, M.; Cobat, A.; Bastard, P.; Lee, Y.S.; Hernandez, N.; Drutman, S.; De Jong, Y.P.; et al. Inherited IL-18BP deficiency in human fulminant viral hepatitis. J. Exp. Med. 2019, 216, 1777–1790. [Google Scholar] [CrossRef]
  90. Novick, D.; Elbirt, D.; Dinarello, C.A.; Rubinstein, M.; Sthoeger, Z.M. Interleukin-18 Binding Protein in the Sera of Patients with Wegener’s Granulomatosis. J. Clin. Immunol. 2009, 29, 38–45. [Google Scholar] [CrossRef]
  91. Novick, D.; Elbirt, D.; Miller, G.; Dinarello, C.A.; Rubinstein, M.; Sthoeger, Z.M. High circulating levels of free interleukin-18 in patients with active SLE in the presence of elevated levels of interleukin-18 binding protein. J. Autoimmun. 2010, 34, 121–126. [Google Scholar] [CrossRef] [PubMed]
  92. Banda, N.K.; Vondracek, A.; Kraus, D.; Dinarello, C.A.; Kim, S.-H.; Bendele, A.; Senaldi, G.; Arend, W.P. Mechanisms of Inhibition of Collagen-Induced Arthritis by Murine IL-18 Binding Protein. J. Immunol. 2003, 170, 2100–2105. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  93. Wada, T.; Muraoka, M.; Yokoyama, T.; Toma, T.; Kanegane, H.; Yachie, A. Cytokine profiles in children with primary Epstein-Barr virus infection. Pediatr. Blood Cancer 2013, 60, E46–E48. [Google Scholar] [CrossRef] [Green Version]
  94. Shimizu, M. Macrophage activation syndrome in systemic juvenile idiopathic arthritis. Immunol. Med. 2021, 44, 237–245. [Google Scholar] [CrossRef] [PubMed]
  95. Maeno, N.; Takei, S.; Imanaka, H.; Yamamoto, K.; Kuriwaki, K.; Kawano, Y.; Oda, H. Increased interleukin-18 expression in bone marrow of a patient with systemic juvenile idiopathic arthritis and unrecognized macrophage-activation syndrome. Arthritis Care Res. 2004, 50, 1935–1938. [Google Scholar] [CrossRef] [PubMed]
  96. Emmenegger, U.; Reimers, A.; Frey, U.; Fux, C.H.; Bihl, F.; Semela, D.; Cottagnoud, P.; Cerny, A.; Spaethe, P.; Neftel, K.A. Reactive macrophage activation syndrome: A simple screening strategy and its potential in early treatment initiation. Swiss Med. Wkly. 2002, 132, 230–236. [Google Scholar] [PubMed]
  97. Nold-Petry, C.A.; Lehrnbecher, T.; Jarisch, A.; Schwabe, D.; Pfeilschifter, J.M.; Muhl, H.; Nold, M.F. Failure of interferon gamma to induce the anti-inflammatory interleukin 18 binding protein in familial hemophagocytosis. PLoS ONE 2010, 5, e8663. [Google Scholar] [CrossRef]
  98. Honda, K.; Ohga, S.; Takada, H.; Nomura, A.; Ohshima, K.; Kinukawa, N.; Mizuno, Y.; Hara, T. Neuron-specific enolase in hemophagocytic lymphohistiocytosis: A potential indicator for macrophage activation? Int. J. Hematol. 2000, 72, 55–60. [Google Scholar]
  99. Fitzgerald, A.A.; LeClercq, S.A.; Yan, A.; Homik, J.E.; Dinarello, C.A. Rapid responses to anakinra in patients with refractory adult-onset Still’s disease. Arthritis Care Res. 2005, 52, 1794–1803. [Google Scholar] [CrossRef]
  100. Larroche, C.; Mouthon, L. Pathogenesis of hemophagocytic syndrome (HPS). Autoimmun. Rev. 2004, 3, 69–75. [Google Scholar] [CrossRef]
  101. Carter, S.J.; Tattersall, R.S.; Ramanan, A.V. Macrophage activation syndrome in adults: Recent advances in pathophysiology, diagnosis and treatment. Rheumatology 2019, 58, 5–17. [Google Scholar] [CrossRef]
  102. Giacomelli, R.; Ruscitti, P.; Shoenfeld, Y. A comprehensive review on adult onset Still’s disease. J. Autoimmun. 2018, 93, 24–36. [Google Scholar] [CrossRef] [PubMed]
  103. Gao, Q.; Yuan, Y.; Wang, Y.; Jiang, J.; Ye, Z.; Liu, T.; Jiang, Z.; Zhao, L. Clinical characteristics of macrophage activation syndrome in adult-onset Still’s disease. Clin. Exp. Rheumatol. 2021, 39 (Suppl. 132), 59–66. [Google Scholar] [CrossRef] [PubMed]
  104. Yasin, S.; Solomon, K.; Canna, S.W.; Girard-Guyonvarc’H, C.; Gabay, C.; Schiffrin, E.; Sleight, A.; Grom, A.A.; Schulert, G.S. IL-18 as therapeutic target in a patient with resistant systemic juvenile idiopathic arthritis and recurrent macrophage activation syndrome. Rheumatology 2020, 59, 442–445. [Google Scholar] [CrossRef]
  105. Behrens, E.M.; Beukelman, T.; Paessler, M.; Cron, R.Q. Occult macrophage activation syndrome in patients with systemic juvenile idiopathic arthritis. J. Rheumatol. 2007, 34, 1133–1138. [Google Scholar] [PubMed]
  106. Crayne, C.B.; Albeituni, S.; Nichols, K.E.; Cron, R.Q. The Immunology of Macrophage Activation Syndrome. Front. Immunol. 2019, 10, 119. [Google Scholar] [CrossRef] [Green Version]
  107. Grom, A.A.; Horne, A.; De Benedetti, F. Macrophage activation syndrome in the era of biologic therapy. Nat. Rev. Rheumatol. 2016, 12, 259–268. [Google Scholar] [CrossRef]
  108. Schulert, G.S.; Grom, A.A. Pathogenesis of Macrophage Activation Syndrome and Potential for Cytokine- Directed Therapies. Annu. Rev. Med. 2015, 66, 145–159. [Google Scholar] [CrossRef] [Green Version]
  109. Kawashima, M.; Yamamura, M.; Taniai, M.; Yamauchi, H.; Tanimoto, T.; Kurimoto, M.; Miyawaki, S.; Amano, T.; Takeuchi, T.; Makino, H. Levels of interleukin-18 and its binding inhibitors in the blood circulation of patients with adult-onset Still’s disease. Arthritis Rheum. 2001, 44, 550–560. [Google Scholar] [CrossRef]
  110. Park, J.H.; Kim, H.-S.; Lee, J.S.; Kim, J.J.; Jung, K.-H.; Park, Y.-W.; Yoo, D.-H. Natural Killer Cell Cytolytic Function in Korean Patients with Adult-onset Still’s Disease. J. Rheumatol. 2012, 39, 2000–2007. [Google Scholar] [CrossRef]
  111. Kawaguchi, Y.; Terajima, H.; Harigai, M.; Hara, M.; Kamatani, N. Interleukin-18 as a novel diagnostic marker and indicator of disease severity in adult-onset Still’s disease. Arthritis Care Res. 2001, 44, 1716–1717. [Google Scholar] [CrossRef]
  112. Colafrancesco, S.; Priori, R.; Alessandri, C.; Perricone, C.; Pendolino, M.; Picarelli, G.; Valesini, G. IL-18 Serum Level in Adult Onset Still’s Disease: A Marker of Disease Activity. Int. J. Inflamm. 2012, 2012, 156890. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  113. Girard, C.; Rech, J.; Brown, M.; Allali, D.; Roux-Lombard, P.; Spertini, F.; Schiffrin, E.J.; Schett, G.; Manger, B.; Bas, S.; et al. Elevated serum levels of free interleukin-18 in adult-onset Still’s disease. Rheumatology 2016, 55, 2237–2247. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  114. Grom, A.A. Macrophage activation syndrome and reactive hemophagocytic lymphohistiocytosis: The same entities? Curr. Opin. Rheumatol. 2003, 15, 587–590. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  115. Grom, A.A.; Mellins, E.D. Macrophage activation syndrome: Advances towards understanding pathogenesis. Curr. Opin. Rheumatol. 2010, 22, 561–566. [Google Scholar] [CrossRef] [PubMed]
  116. Grom, A.A.; Villanueva, J.; Lee, S.; Goldmuntz, E.A.; Passo, M.H.; Filipovich, A. Natural killer cell dysfunction in patients with systemic-onset juvenile rheumatoid arthritis and macrophage activation syndrome. J. Pediatr. 2003, 142, 292–296. [Google Scholar] [CrossRef]
  117. Villanueva, J.; Lee, S.; Giannini, E.H.; Graham, T.B.; Passo, M.H.; Filipovich, A.; Grom, A.A. Natural killer cell dysfunction is a distinguishing feature of systemic onset juvenile rheumatoid arthritis and macrophage activation syndrome. Arthritis Res. Ther. 2005, 7, R30–R37. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  118. Janka, G. Familial and Acquired Hemophagocytic Lymphohistiocytosis. Annu. Rev. Med. 2012, 63, 233–246. [Google Scholar] [CrossRef]
  119. Chen, O.; Shan, N.; Zhu, X.; Wang, Y.; Ren, P.; Wei, D.E.; Sun, R. The imbalance of IL-18/IL-18BP in patients with systemic juvenile idiopathic arthritis. Acta Biochim. Biophys. Sin. 2013, 45, 339–341. [Google Scholar] [CrossRef] [Green Version]
  120. Weiss, E.S.; Girard-Guyonvarc’h, C.; Holzinger, D.; de Jesus, A.A.; Tariq, Z.; Picarsic, J.; Schiffrin, E.J.; Foell, D.; Grom, A.A.; Ammann, S.; et al. Interleukin-18 diagnostically distinguishes and pathogenically promotes human and murine macrophage activation syndrome. Blood 2018, 131, 1442–1455. [Google Scholar] [CrossRef]
  121. Jelušić, M.; Lukić, I.K.; Tambić-Bukovac, L.; Dubravčić, K.; Malčić, I.; Rudan, I.; Batinić, D. Interleukin-18 as a mediator of systemic juvenile idiopathic arthritis. Clin. Rheumatol. 2007, 26, 1332–1334. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  122. Lotito AP, N.; Campa, A.; Silva, C.A.; Kiss, M.H.; Mello, S.B. Interleukin 18 as a marker of disease activity and severity in patients with juvenile idiopathic arthritis. J. Rheumatol. 2007, 34, 823–830. [Google Scholar] [PubMed]
  123. Kim, H.A.; An, J.M.; Nam, J.Y.; Jeon, J.Y.; Suh, C.H. Serum S100A8/A9, but not follistatin-like protein 1 and interleukin 18, may be a useful biomarker of disease activity in adult-onset Still’s disease. J. Rheumatol. 2012, 39, 1399–1406. [Google Scholar] [CrossRef] [PubMed]
  124. Shimizu, M.; Nakagishi, Y.; Inoue, N.; Mizuta, M.; Ko, G.; Saikawa, Y.; Kubota, T.; Yamasaki, Y.; Takei, S.; Yachie, A. Interleukin-18 for predicting the development of macrophage activation syndrome in systemic juvenile idiopathic arthritis. Clin. Immunol. 2015, 160, 277–281. [Google Scholar] [CrossRef] [PubMed]
  125. Put, K.; Avau, A.; Brisse, E.; Mitera, T.; Put, S.; Proost, P.; Bader-Meunier, B.; Westhovens, R.; van den Eynde, B.J.; Orabona, C.; et al. Cytokines in systemic juvenile idiopathic arthritis and haemophagocytic lymphohistiocytosis: Tipping the balance between interleukin-18 and interferon-gamma. Rheumatology 2015, 54, 1507–1517. [Google Scholar]
  126. Inoue, N.; Shimizu, M.; Tsunoda, S.; Kawano, M.; Matsumura, M.; Yachie, A. Cytokine profile in adult-onset Still’s disease: Comparison with systemic juvenile idiopathic arthritis. Clin. Immunol. 2016, 169, 8–13. [Google Scholar] [CrossRef] [Green Version]
  127. Tomaras, S.; Goetzke, C.; Kallinich, T.; Feist, E. Adult-Onset Still’s Disease: Clinical Aspects and Therapeutic Approach. J. Clin. Med. 2021, 10, 733. [Google Scholar] [CrossRef]
  128. Tang, S.; Li, S.; Zheng, S.; Ding, Y.; Zhu, D.; Sun, C.; Hu, Y.; Qiao, J.; Fang, H. Understanding of cytokines and targeted therapy in macrophage activation syndrome. Semin. Arthritis Rheum. 2021, 51, 198–210. [Google Scholar] [CrossRef]
  129. Gabay, C.; Fautrel, B.; Rech, J.; Spertini, F.; Feist, E.; Kötter, I.; Hachulla, E.; Morel, J.; Schaeverbeke, T.; Hamidou, M.A.; et al. Open-label, multicentre, dose-escalating phase II clinical trial on the safety and efficacy of tadekinig alfa (IL-18BP) in adult-onset Still’s disease. Ann. Rheum. Dis. 2018, 77, 840–847. [Google Scholar] [CrossRef]
  130. Kiltz, U.; Kiefer, D.; Braun, J.; Schiffrin, E.J.; Girard-Guyonvarc’H, C.; Gabay, C. Prolonged treatment with Tadekinig alfa in adult-onset Still’s disease. Ann. Rheum. Dis. 2020, 79, e10. [Google Scholar] [CrossRef]
  131. Canna, S.W.; Girard, C.; Malle, L.; de Jesus, A.; Romberg, N.; Kelsen, J.; Surrey, L.F.; Russo, P.; Sleight, A.; Schiffrin, E.; et al. Life-threatening NLRC4-associated hyperinflammation successfully treated with IL-18 inhibition. J. Allergy Clin. Immunol. 2017, 139, 1698–1701. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  132. Liao, T.L.; Chen, Y.M.; Hsieh, C.W.; Chen, H.H.; Lee, H.C.; Hung, W.T.; Tang, K.-Y.; Chen, D.Y. Upregulation of circulating microRNA-134 in adult-onset Still’s disease and its use as potential biomarker. Sci. Rep. 2017, 7, 4214. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  133. O’Brien, J.; Hayder, H.; Zayed, Y.; Peng, C. Overview of MicroRNA Biogenesis, Mechanisms of Actions, and Circulation. Front. Endocrinol. 2018, 9, 402. [Google Scholar] [CrossRef] [Green Version]
  134. Canna, S.W.; De Jesus, A.A.; Gouni, S.; Brooks, S.R.; Marrero, B.; Liu, Y.; DiMattia, M.A.; Zaal, K.J.; Sanchez, G.A.M.; Kim, H.; et al. An activating NLRC4 inflammasome mutation causes autoinflammation with recurrent macrophage activation syndrome. Nat. Genet. 2014, 46, 1140–1146. [Google Scholar] [CrossRef] [Green Version]
  135. Romberg, N.; Al Moussawi, K.; Nelson-Williams, C.; Stiegler, A.L.; Loring, E.; Choi, M.; Overton, J.; Meffre, E.; Khokha, M.K.; Huttner, A.J.; et al. Mutation of NLRC4 causes a syndrome of enterocolitis and autoinflammation. Nat. Genet. 2014, 46, 1135–1139. [Google Scholar] [CrossRef] [Green Version]
  136. Dinarello, C.A. Targeting interleukin 18 with interleukin 18 binding protein. Ann. Rheum. Dis. 2000, 59 (Suppl. 1), i17–i20. [Google Scholar] [CrossRef]
  137. Vasilev, G.; Manolova, I.; Ivanova, M.; Stanilov, I.; Miteva, L.; Stanilova, S. The role of IL-18 in addition to Th17 cytokines in rheumatoid arthritis development and treatment in women. Sci. Rep. 2021, 11, 15391. [Google Scholar] [CrossRef] [PubMed]
  138. Xu, M.-H.; Yuan, F.-L.; Wang, S.-J.; Xu, H.-Y.; Li, C.-W.; Tong, X. Association of interleukin-18 and asthma. Inflammation 2017, 40, 324–327. [Google Scholar] [CrossRef]
  139. Xiang, M.; Feng, Y.; Wang, Y.; Wang, J.; Zhang, Z.; Liang, J.; Xu, J. Correlation between circulating interleukin-18 level and systemic lupus erythematosus: A meta-analysis. Sci. Rep. 2021, 11, 4707. [Google Scholar] [CrossRef]
  140. Forouzandeh, M.; Besen, J.; Keane, R.W.; Vaccari, J.P.D.R. The Inflammasome Signaling Proteins ASC and IL-18 as Biomarkers of Psoriasis. Front. Pharmacol. 2020, 11, 1238. [Google Scholar] [CrossRef]
  141. Fukaura, H.; Kikuchi, S. [IL-18 in multiple sclerosis]. Nihon Rinsho 2003, 61, 1416–1421. [Google Scholar]
  142. Franke, E.I.; Vanderbrink, B.A.; Hile, K.L.; Zhang, H.; Cain, A.; Matsui, F.; Meldrum, K.K. Renal IL-18 Production Is Macrophage Independent During Obstructive Injury. PLoS ONE 2012, 7, e47417. [Google Scholar] [CrossRef]
  143. Williams, M.; O’Callaghan, A.; Corr, S.C. IL-33 and IL-18 in Inflammatory Bowel Disease Etiology and Microbial Interactions. Front. Immunol. 2019, 10, 1091. [Google Scholar] [CrossRef] [Green Version]
  144. Su, Y.; Zhao, H. Predisposition of Inflammatory Bowel Disease Is Influenced by IL-8, IL-10, and IL-18 Polymorphisms: A Meta-Analysis. Int. Arch. Allergy Immunol. 2020, 181, 799–806. [Google Scholar] [CrossRef]
  145. Karaba, A.H.; Figueroa, A.; Werbel, W.A.; Dioverti, M.V.; Steinke, S.M.; Ray, S.C.; Cox, A.L.; Avery, R.K. Interleukin-18 and tumor necrosis factor-α are elevated in solid organ transplant recipients with possible cytomegalovirus end-organ disease. Transpl. Infect. Dis. 2021, 23, e13682. [Google Scholar] [CrossRef] [PubMed]
  146. Liu, C.; Chen, J.; Liu, B.; Yuan, S.; Shou, D.; Wen, L.; Wu, X.; Gong, W. Role of IL-18 in transplant biology. Eur. Cytokine Netw. 2018, 29, 48–51. [Google Scholar] [CrossRef] [PubMed]
  147. Park, H.J.; Kim, J.E.; Lee, J.Y.; Cho, B.K.; Lee, W.J.; Kim, T.; Yoon, D.; Cho, D. Increased expression of IL-18 in cutaneous graft-versus-host disease. Immunol. Lett. 2004, 95, 57–61. [Google Scholar] [CrossRef] [PubMed]
  148. Stone, D.L.; Ombrello, A.; Arostegui, J.I.; Schneider, C.; Dang, V.; de Jesus, A.; Girard-Guyonvarc’H, C.; Gabay, C.; Lee, W.; Chae, J.J.; et al. Excess Serum Interleukin-18 Distinguishes Patients With Pathogenic Mutations in PSTPIP1. Arthritis Rheumatol. 2022, 74, 353–357. [Google Scholar] [CrossRef] [PubMed]
  149. Wise, C.A.; Gillum, J.D.; Seidman, C.E.; Lindor, N.M.; Veile, R.; Bashiardes, S.; Lovett, M. Mutations in CD2BP1 disrupt binding to PTP PEST and are responsible for PAPA syndrome, an autoinflammatory disorder. Hum. Mol. Genet. 2002, 11, 961–969. [Google Scholar] [CrossRef]
  150. Shoham, N.G.; Centola, M.; Mansfield, E.; Hull, K.M.; Wood, G.; Wise, C.A.; Kastner, D.L. Pyrin binds the PSTPIP1/CD2BP1 protein, defining familial Mediterranean fever and PAPA syndrome as disorders in the same pathway. Proc. Natl. Acad. Sci. USA 2003, 100, 13501–13506. [Google Scholar] [CrossRef] [Green Version]
  151. Wlodek, E.; Kirkpatrick, R.B.; Andrews, S.; Noble, R.; Schroyer, R.; Scott, J.; Watson, C.J.E.; Clatworthy, M.; Harrison, E.M.; Wigmore, S.J.; et al. A pilot study evaluating GSK1070806 inhibition of interleukin-18 in renal transplant delayed graft function. PLoS ONE 2021, 16, e0247972. [Google Scholar] [CrossRef] [PubMed]
  152. Galozzi, P.; Bindoli, S.; Doria, A.; Sfriso, P. Progress in Biological Therapies for Adult-Onset Still’s Disease. Biol. Targets Ther. 2022, 16, 21–34. [Google Scholar] [CrossRef]
  153. Detry, S.; Andries, J.; Bloch, Y.; Gabay, C.; Clancy, D.M.; Savvides, S.N. Structural basis of human IL-18 sequestration by the decoy receptor IL-18 binding protein (IL-18BP) in inflammation and tumor immunity. J. Biol. Chem. 2022, 298, 101808. [Google Scholar] [CrossRef] [PubMed]
  154. Flament, H.; Rouland, M.; Beaudoin, L.; Toubal, A.; Bertrand, L.; Lebourgeois, S.; Rousseau, C.; Soulard, P.; Gouda, Z.; Cagninacci, L.; et al. Outcome of SARS-CoV-2 infection is linked to MAIT cell activation and cytotoxicity. Nat. Immunol. 2021, 22, 322–335. [Google Scholar] [CrossRef] [PubMed]
  155. Lucas, C.; Wong, P.; Klein, J.; Castro, T.B.R.; Silva, J.; Sundaram, M.; Ellingson, M.K.; Mao, T.; Oh, J.E.; Israelow, B.; et al. Longitudinal analyses reveal immunological misfiring in severe COVID-19. Nature 2020, 584, 463–469. [Google Scholar] [CrossRef]
  156. Rodriguez-Smith, J.J.; Verweyen, E.L.; Clay, G.M.; Esteban, Y.M.; de Loizaga, S.R.; Baker, E.J.; Do, T.; Dhakal, S.; Lang, S.M.; Grom, A.A.; et al. Inflammatory biomarkers in COVID-19-associated multisystem inflammatory syndrome in children, Kawasaki disease, and macrophage activation syndrome: A cohort study. Lancet Rheumatol. 2021, 3, e574–e584. [Google Scholar] [CrossRef]
  157. Huang, W.; Li, M.; Luo, G.; Wu, X.; Su, B.; Zhao, L.; Zhang, S.; Chen, X.; Jia, M.; Zhu, J.; et al. The inflammatory factors associated with disease severity to predict COVID-19 progression. J. Immunol. 2021, 206, 1597–1608. [Google Scholar] [CrossRef]
  158. Karki, R.; Sharma, B.R.; Tuladhar, S.; Williams, E.P.; Zalduondo, L.; Samir, P.; Zheng, M.; Sundaram, B.; Banoth, B.; Malireddi, R.K.S.; et al. Synergism of TNF-alpha and IFN-gamma Triggers Inflammatory Cell Death, Tissue Damage, and Mortality in SARS-CoV-2 Infection and Cytokine Shock Syndromes. Cell 2021, 184, 149–168.e17. [Google Scholar] [CrossRef]
  159. Wilson, J.G.; Simpson, L.J.; Ferreira, A.-M.; Rustagi, A.; Roque, J.; Asuni, A.; Ranganath, T.; Grant, P.M.; Subramanian, A.; Rosenberg-Hasson, Y.; et al. Cytokine profile in plasma of severe COVID-19 does not differ from ARDS and sepsis. JCI Insight 2020, 5, 140289. [Google Scholar] [CrossRef]
  160. Gerasimenko, V.J.; Petersen, O.H.; Gerasimenko, O.V. SARS-CoV-2 S Protein Subunit 1 Elicits Ca2+ Influx - Dependent Ca2+ Signals in Pancreatic Stellate Cells and Macrophages In Situ. Function 2022, 3, zqac002. [Google Scholar] [CrossRef]
  161. Jamilloux, Y.; Henry, T.; Belot, A.; Viel, S.; Fauter, M.; El Jammal, T.; Walzer, T.; François, B.; Sève, P. Should we stimulate or suppress immune responses in COVID-19? Cytokine and anti-cytokine interventions. Autoimmun. Rev. 2020, 19, 102567. [Google Scholar] [CrossRef] [PubMed]
Biomedicines 10 01750 g001 550
Figure 1. IL-18BP Biological Role. Left panel, ① danger stimuli, such as pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), activate the Toll-like receptors (TLR) signaling pathway that triggers MyD88, TRAF, inflammasome oligomerization that leads to subsequent activation of caspase-1 (Cas1). Consequently, the translocation of the NF-κB takes place and leads to ② the production of proinflammatory cytokines, including inductions of the transcriptional activation of pro-interleukin IL-18 (pro-IL-18), which is proteolytically cleaved and converted to its mature active form via the active caspase-1 (Cas1), then ③ IL-18 is secreted from the cell. Right panel, ④ when secreted IL-18 binds to the cells expressing IL-18R (mainly monocytes, NK cells, and T cells) and activates the respective signaling pathways, for example, MAPKs and NF-κB activation, which in turn leads to the ⑤ expression of proinflammatory molecules and induce the production of IFNγ. Next, IFNγ activates macrophages and allows them to produce inflammatory cytokines. This IFNγ induction and the activation cascade of IL-18 is inhibited by its natural neutralizing soluble inhibitor, interleukin IL-18 binding protein (IL-18BP).
Figure 1. IL-18BP Biological Role. Left panel, ① danger stimuli, such as pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), activate the Toll-like receptors (TLR) signaling pathway that triggers MyD88, TRAF, inflammasome oligomerization that leads to subsequent activation of caspase-1 (Cas1). Consequently, the translocation of the NF-κB takes place and leads to ② the production of proinflammatory cytokines, including inductions of the transcriptional activation of pro-interleukin IL-18 (pro-IL-18), which is proteolytically cleaved and converted to its mature active form via the active caspase-1 (Cas1), then ③ IL-18 is secreted from the cell. Right panel, ④ when secreted IL-18 binds to the cells expressing IL-18R (mainly monocytes, NK cells, and T cells) and activates the respective signaling pathways, for example, MAPKs and NF-κB activation, which in turn leads to the ⑤ expression of proinflammatory molecules and induce the production of IFNγ. Next, IFNγ activates macrophages and allows them to produce inflammatory cytokines. This IFNγ induction and the activation cascade of IL-18 is inhibited by its natural neutralizing soluble inhibitor, interleukin IL-18 binding protein (IL-18BP).
Biomedicines 10 01750 g001
Biomedicines 10 01750 g002 550
Figure 2. IL-18BP expression induced by IFNγ. IFNγ production is induced due to cytokines that are released in response to infection, tissue damage, activation of pattern recognition receptors (PRRs) or reactive antigen stimulation. Left side (up), the upregulated IL-18BP triggers the negative feedback loop, which in turn allows IL-18BP to inhibit the production of IFNγ. Left side (down), the epigenetic regulation of IL-18BP in various cells, methylation at the IL-18BP promoter region controls its expression upon IFNγ stimulation. Epithelial cells have no CpG methylation; therefore, their IL-18BP inducibility is strong and higher than monocytic cells, which have CpG methylation. Right side, IFNγ signaling starts when it binds to its receptor IFNγR, which consists of two subunits, IFNγR1 and IFNγR2. Later, this binding induces the Janus kinase (JAK) signal transducer and activator of transcription (STAT) signaling, particularly STAT1 makes a dimer, and then cooperates with IFNγ-induced interferon regulatory factors (IRFs), resulting in translocation into the nucleus. IL-18BP promoter holds several response elements, among them IFN regulatory factor 1 response element (IRF-E) and STAT1. These transcriptional activations of the promoter induce IL-18BP expression.
Figure 2. IL-18BP expression induced by IFNγ. IFNγ production is induced due to cytokines that are released in response to infection, tissue damage, activation of pattern recognition receptors (PRRs) or reactive antigen stimulation. Left side (up), the upregulated IL-18BP triggers the negative feedback loop, which in turn allows IL-18BP to inhibit the production of IFNγ. Left side (down), the epigenetic regulation of IL-18BP in various cells, methylation at the IL-18BP promoter region controls its expression upon IFNγ stimulation. Epithelial cells have no CpG methylation; therefore, their IL-18BP inducibility is strong and higher than monocytic cells, which have CpG methylation. Right side, IFNγ signaling starts when it binds to its receptor IFNγR, which consists of two subunits, IFNγR1 and IFNγR2. Later, this binding induces the Janus kinase (JAK) signal transducer and activator of transcription (STAT) signaling, particularly STAT1 makes a dimer, and then cooperates with IFNγ-induced interferon regulatory factors (IRFs), resulting in translocation into the nucleus. IL-18BP promoter holds several response elements, among them IFN regulatory factor 1 response element (IRF-E) and STAT1. These transcriptional activations of the promoter induce IL-18BP expression.
Biomedicines 10 01750 g002
Biomedicines 10 01750 g003 550
Figure 3. IL-18BP isoforms. Multiple sequence alignment for the isoforms of human IL-18BP. PTM features are indicated as glycosylation sites, which are displayed above the sequence (N-linked; Triangle, O-linked; circle, blue for confirmed, red for predicted O-glycosylation). Disulfide bridges are exposed as dashed lines (red and orange). Residues with homology are indicated with an asterisk (*) below the residue. Residues shearing identity with the virus IL-18BP are highlighted within an orange color shaded box. The domain of Ig-like C2-type is highlighted in green (starts at 65 and ends at 166 with a length of 102aa based on the sequence of IL-18BPa). Uniport accession number; IL-18BPa (O95998 I18BP_HUMAN/NP_766630.2), IL-18BPb (O95998-3 I18BP_HUMAN/NP_001138527.1), IL-18BPd (O95998-4 I18BP_HUMAN/NP_766632.2), and IL-18BPc (G3V1C5 _HUMAN/NP_005690.2). (:) Conservative residue; (.) Semi-conservative residue; ( ) Non-conservative residue.
Figure 3. IL-18BP isoforms. Multiple sequence alignment for the isoforms of human IL-18BP. PTM features are indicated as glycosylation sites, which are displayed above the sequence (N-linked; Triangle, O-linked; circle, blue for confirmed, red for predicted O-glycosylation). Disulfide bridges are exposed as dashed lines (red and orange). Residues with homology are indicated with an asterisk (*) below the residue. Residues shearing identity with the virus IL-18BP are highlighted within an orange color shaded box. The domain of Ig-like C2-type is highlighted in green (starts at 65 and ends at 166 with a length of 102aa based on the sequence of IL-18BPa). Uniport accession number; IL-18BPa (O95998 I18BP_HUMAN/NP_766630.2), IL-18BPb (O95998-3 I18BP_HUMAN/NP_001138527.1), IL-18BPd (O95998-4 I18BP_HUMAN/NP_766632.2), and IL-18BPc (G3V1C5 _HUMAN/NP_005690.2). (:) Conservative residue; (.) Semi-conservative residue; ( ) Non-conservative residue.
Biomedicines 10 01750 g003
Biomedicines 10 01750 g004 550
Figure 4. IL-18BP inhibiting IL-18 target cells and therapeutic interventions. IL-18 assists several immune cells, it stimulates NK to produce IFNγ, which activates macrophages and allows them to produce inflammatory cytokines. In addition, it participates in the Th1 and Th2 response, depending on cytokine partners, when IL-18 is combined with IL-12 it facilitates the Th1 immune response, which in turn activates DCs and releases inflammatory cytokines, such as IFNγ and TNFα. In response to Th1 activation, M1 macrophages induce IL-18 and supply the loop. Alternatively, in the absence of IL-12, and when IL-18 is combined with IL-2 and/or IL-4, together they facilitate Th2 immune response, which in turn secreted IgE and numerous Th2 cytokines, such as IL-4, IL-5, IL-9, and IL-13. In response to Th2 activation, M2 macrophages and/or mast cells become activated, and then the production of histamine takes place (allergic response), which is also facilitated when IL-18 is combined with IL-3. When IL-18BP sequestered IL-18, the following activated cascade is inhibited. Therefore, IL-18BP can play potential roles in both Th1 and Th2 autoimmune diseases. Boxes indicated the main pathological condition (RED), potential therapeutic options (BLUE; anticancer molecules in the clinical trial, GREEN; IL-18BP or equivalent; Tadekinig-α, GSK1070806, and APB-3R are in clinical and pre-clinical trials, IL-18BPΔN-EH showed higher affinity than full-length IL-18BP and suggested for use in treating autoimmune diseases).
Figure 4. IL-18BP inhibiting IL-18 target cells and therapeutic interventions. IL-18 assists several immune cells, it stimulates NK to produce IFNγ, which activates macrophages and allows them to produce inflammatory cytokines. In addition, it participates in the Th1 and Th2 response, depending on cytokine partners, when IL-18 is combined with IL-12 it facilitates the Th1 immune response, which in turn activates DCs and releases inflammatory cytokines, such as IFNγ and TNFα. In response to Th1 activation, M1 macrophages induce IL-18 and supply the loop. Alternatively, in the absence of IL-12, and when IL-18 is combined with IL-2 and/or IL-4, together they facilitate Th2 immune response, which in turn secreted IgE and numerous Th2 cytokines, such as IL-4, IL-5, IL-9, and IL-13. In response to Th2 activation, M2 macrophages and/or mast cells become activated, and then the production of histamine takes place (allergic response), which is also facilitated when IL-18 is combined with IL-3. When IL-18BP sequestered IL-18, the following activated cascade is inhibited. Therefore, IL-18BP can play potential roles in both Th1 and Th2 autoimmune diseases. Boxes indicated the main pathological condition (RED), potential therapeutic options (BLUE; anticancer molecules in the clinical trial, GREEN; IL-18BP or equivalent; Tadekinig-α, GSK1070806, and APB-3R are in clinical and pre-clinical trials, IL-18BPΔN-EH showed higher affinity than full-length IL-18BP and suggested for use in treating autoimmune diseases).
Biomedicines 10 01750 g004
Table
Table 1. Clinical trials associated with IL-18.
Table 1. Clinical trials associated with IL-18.
Condition/DiseaseClinical PhaseClinical Trial StatusNo. of ParticipantsType of Intervention or
Treatment		NCT Number
Still’s Disease, Adult-OnsetPhase IICompleted23 participantsBiological: Tadekinig alfa (recombinant human IL-18 binding protein)NCT02398435
XIAP Deficiency, NLRC4-MASPhase IIIRecruiting10 participantsDrug: Tadekinig alfaNCT03512314
XIAP Deficiency, NLRC4-MASPhase IIIRecruiting10 participantsDrug: Tadekinig alfaNCT03113760
Inflammatory Bowel DiseasesPhase ICompleted78 participantsDrug: GSK1070806 (block IL-18)NCT01035645
Kidney Transplantation (Status Post)Phase IITerminated *7 participantsDrug: GSK1070806 + othersNCT02723786
MelanomaPhase IICompleted64 participantsDrug: SB-485232 (rhIL-18)NCT00107718
Dermatitis, AtopicPhase IRecruiting48 participantsDrug: GSK1070806NCT04975438
Crohn DiseasePhase I
Phase II		Completed5 participantsDrug: GSK1070806NCT03681067
Behcet’s DiseasePhase IIUnknown #12 participantsDrug: GSK1070806NCT03522662
* Lack of efficacy. # Study has passed its completion date and status has not been verified in more than 2 years.
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Park, S.Y.; Hisham, Y.; Shin, H.M.; Yeom, S.C.; Kim, S. Interleukin-18 Binding Protein in Immune Regulation and Autoimmune Diseases. Biomedicines 2022, 10, 1750. https://doi.org/10.3390/biomedicines10071750

AMA Style

Park SY, Hisham Y, Shin HM, Yeom SC, Kim S. Interleukin-18 Binding Protein in Immune Regulation and Autoimmune Diseases. Biomedicines. 2022; 10(7):1750. https://doi.org/10.3390/biomedicines10071750

Chicago/Turabian Style

Park, Seung Yong, Yasmin Hisham, Hyun Mu Shin, Su Cheong Yeom, and Soohyun Kim. 2022. "Interleukin-18 Binding Protein in Immune Regulation and Autoimmune Diseases" Biomedicines 10, no. 7: 1750. https://doi.org/10.3390/biomedicines10071750

APA Style

Park, S. Y., Hisham, Y., Shin, H. M., Yeom, S. C., & Kim, S. (2022). Interleukin-18 Binding Protein in Immune Regulation and Autoimmune Diseases. Biomedicines, 10(7), 1750. https://doi.org/10.3390/biomedicines10071750

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop