Vaccines

2024

Jump to: 2022, 2021, 2020

27 pages, 6460 KiB

Open AccessReview

New Emerging Targets in Cancer Immunotherapy: The Role of B7-H3

by Ioannis-Alexios Koumprentziotis, Charalampos Theocharopoulos, Dimitra Foteinou, Erasmia Angeli, Amalia Anastasopoulou, Helen Gogas and Dimitrios C. Ziogas

Vaccines 2024, 12(1), 54; https://doi.org/10.3390/vaccines12010054 - 5 Jan 2024

Cited by 5 | Viewed by 4504

Abstract

Immune checkpoints (ICs) are molecules implicated in the fine-tuning of immune response via co-inhibitory or co-stimulatory signals, and serve to secure minimized host damage. Targeting ICs with various therapeutic modalities, including checkpoint inhibitors/monoclonal antibodies (mAbs), antibody-drug conjugates (ADCs), and CAR-T cells has produced [...] Read more.

Immune checkpoints (ICs) are molecules implicated in the fine-tuning of immune response via co-inhibitory or co-stimulatory signals, and serve to secure minimized host damage. Targeting ICs with various therapeutic modalities, including checkpoint inhibitors/monoclonal antibodies (mAbs), antibody-drug conjugates (ADCs), and CAR-T cells has produced remarkable results, especially in immunogenic tumors, setting a paradigm shift in cancer therapeutics through the incorporation of these IC-targeted treatments. However, the large proportion of subjects who experience primary or secondary resistance to available IC-targeted options necessitates further advancements that render immunotherapy beneficial for a larger patient pool with longer duration of response. B7-H3 (B7 Homolog 3 Protein, CD276) is a member of the B7 family of IC proteins that exerts pleiotropic immunomodulatory effects both in physiologic and pathologic contexts. Mounting evidence has demonstrated an aberrant expression of B7-H3 in various solid malignancies, including tumors less sensitive to current immunotherapeutic options, and has associated its expression with advanced disease, worse patient survival and impaired response to IC-based regimens. Anti-B7-H3 agents, including novel mAbs, bispecific antibodies, ADCs, CAR-T cells, and radioimmunotherapy agents, have exhibited encouraging antitumor activity in preclinical models and have recently entered clinical testing for several cancer types. In the present review, we concisely present the functional implications of B7-H3 and discuss the latest evidence regarding its prognostic significance and therapeutic potential in solid malignancies, with emphasis on anti-B7-H3 modalities that are currently evaluated in clinical trial settings. Better understanding of B7-H3 intricate interactions in the tumor microenvironment will expand the oncological utility of anti-B7-H3 agents and further shape their role in cancer therapeutics. Full article

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2022

Jump to: 2024, 2021, 2020

15 pages, 6951 KiB

Open AccessArticle

Protective Human Anti-Poxvirus Monoclonal Antibodies Are Generated from Rare Memory B Cells Isolated by Multicolor Antigen Tetramers

by Xiuling Gu, Yufan Zhang, Wei Jiang, Dongfang Wang, Jiao Lu, Guanglei Gu, Chengfeng Qin and Min Fang

Vaccines 2022, 10(7), 1084; https://doi.org/10.3390/vaccines10071084 - 6 Jul 2022

Cited by 12 | Viewed by 3112

Abstract

Smallpox, an epidemic disease caused by Orthopoxvirus variola, was eradicated worldwide through immunization. The immunization against smallpox was discontinued in 1980. However, incidences of monkeypox virus infection in humans have occurred sporadically, and there is also great fear that engineered forms of [...] Read more.

Smallpox, an epidemic disease caused by Orthopoxvirus variola, was eradicated worldwide through immunization. The immunization against smallpox was discontinued in 1980. However, incidences of monkeypox virus infection in humans have occurred sporadically, and there is also great fear that engineered forms of poxvirus could be used as biological weapons. Therefore, monoclonal antibodies against poxvirus are urgently needed for the detection and treatment of poxvirus infection. The vaccinia virus’ extracellular envelope protein A33 is a potential candidate for a subunit vaccine. We used multi-fluorescence-labeled tetrameric A33 antigen to identify rare poxvirus-specific memory B cells from the PBMC of volunteers with vaccinia virus immunization more than 40 years ago. Despite extremely low frequencies of the poxvirus-specific memory B cells, we successfully sorted A33 tetramer-labeled single memory B cells and reconstructed the antibodies with the single-cell RT-PCR of the B-cell receptor. Among the monoclonal antibodies, one clone H2 exhibited high specificity and affinity with A33. H2 efficiently inhibited viral infection and spread in cells. Passive immunotherapy of H2 in mice protected mice from lethal infection when administered either prophylactically or therapeutically. These results suggest the potential of anti-A33 human-antibody-based detection and therapeutics for poxvirus infection. Full article

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11 pages, 1582 KiB

Open AccessArticle

Natural Brucella melitensis Infection and Rev. 1 Vaccination Induce Specific Brucella O-Polysaccharide Antibodies Involved in Complement Mediated Brucella Cell Killing

by Shubham Mathur, Menachem Banai and Dani Cohen

Vaccines 2022, 10(2), 317; https://doi.org/10.3390/vaccines10020317 - 17 Feb 2022

Cited by 7 | Viewed by 2550

Abstract

Vaccination against brucellosis using live attenuated strains is the primary approach in protecting livestock against the disease through a strong cellular immune response. Attenuated vaccine strains also induce serum anti-Brucella antibodies, mostly against Brucella O-polysaccharide, but their role in protection against the [...] Read more.

Vaccination against brucellosis using live attenuated strains is the primary approach in protecting livestock against the disease through a strong cellular immune response. Attenuated vaccine strains also induce serum anti-Brucella antibodies, mostly against Brucella O-polysaccharide, but their role in protection against the disease remains unclear. In this study, we show that Brucella OPS serum antibodies after vaccination or natural infection could kill Brucella in vitro as shown by the serum bactericidal activity (SBA) assay. We used serum samples of Rev. 1 vaccinated sheep that were negative or positive for Brucella OPS antibodies by either one of complement fixation test (CFT), microplate agglutination test (MAT) and ELISA, or sera of naturally infected sheep positive by CFT. We found a significant increase in the killing ability of sera 30 days after intraocular vaccination with Rev. 1 as compared with pre-vaccination. SBA was significantly higher in sera containing Brucella OPS IgG antibodies in comparison with sera lacking such antibodies (p < 0.001 against 16M & Rev. 1 strains). All 10 sera of convalescent sheep demonstrated significant killing ability against the 16M B. melitensis field strain. Specific OPS antibodies participate in the in vitro complement mediated Brucella killing suggesting a potential role in protection against the disease through this mechanism and relevance of developing OPS-based Brucella vaccines. Full article

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2021

Jump to: 2024, 2022, 2020

12 pages, 2713 KiB

Open AccessArticle

Anti-IAPP Monoclonal Antibody Improves Clinical Symptoms in a Mouse Model of Type 2 Diabetes

by Anne-Cathrine S. Vogt, Elisa S. Roesti, Mona O. Mohsen, Ainars Leonchiks, Monique Vogel and Martin F. Bachmann

Vaccines 2021, 9(11), 1316; https://doi.org/10.3390/vaccines9111316 - 12 Nov 2021

Cited by 8 | Viewed by 3363

Abstract

Type 2 Diabetes Mellitus (T2DM) is a chronic progressive disease, defined by insulin resistance and insufficient insulin secretion to maintain normoglycemia. Amyloidogenic aggregates are a hallmark of T2DM patients; they are cytotoxic for the insulin producing β-cells, and cause inflammasome-dependent secretion of IL-1β. [...] Read more.

Type 2 Diabetes Mellitus (T2DM) is a chronic progressive disease, defined by insulin resistance and insufficient insulin secretion to maintain normoglycemia. Amyloidogenic aggregates are a hallmark of T2DM patients; they are cytotoxic for the insulin producing β-cells, and cause inflammasome-dependent secretion of IL-1β. To avoid the associated β-cell loss and inflammation in advanced stage T2DM, we developed a novel monoclonal therapy targeting the major component of aggregates, islet amyloid polypeptide (IAPP). The here described monoclonal antibody (mAb) m81, specific for oligomeric and fibrils, but not for soluble free IAPP, is able to prevent oligomer growth and aggregate formation in vitro, and blocks islet inflammation and disease progression in vivo. Collectively, our data show that blocking fibril formation and prevention of new amyloidogenic aggregates by monoclonal antibody therapy may be a potential therapy for T2DM. Full article

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20 pages, 787 KiB

Open AccessReview

Antibody-Drug Conjugates: Functional Principles and Applications in Oncology and Beyond

by Charalampos Theocharopoulos, Panagiotis-Petros Lialios, Michael Samarkos, Helen Gogas and Dimitrios C. Ziogas

Vaccines 2021, 9(10), 1111; https://doi.org/10.3390/vaccines9101111 - 29 Sep 2021

Cited by 29 | Viewed by 9321

Abstract

In the era of precision medicine, antibody-based therapeutics are rapidly enriched with emerging advances and new proof-of-concept formats. In this context, antibody-drug conjugates (ADCs) have evolved to merge the high selectivity and specificity of monoclonal antibodies (mAbs) with the cytotoxic potency of attached [...] Read more.

In the era of precision medicine, antibody-based therapeutics are rapidly enriched with emerging advances and new proof-of-concept formats. In this context, antibody-drug conjugates (ADCs) have evolved to merge the high selectivity and specificity of monoclonal antibodies (mAbs) with the cytotoxic potency of attached payloads. So far, ten ADCs have been approved by FDA for oncological indications and many others are currently being tested in clinical and preclinical level. This paper summarizes the essential components of ADCs, from their functional principles and structure up to their limitations and resistance mechanisms, focusing on all latest bioengineering breakthroughs such as bispecific mAbs, dual-drug platforms as well as novel linkers and conjugation chemistries. In continuation of our recent review on anticancer implication of ADC’s technology, further insights regarding their potential usage outside of the oncological spectrum are also presented. Better understanding of immunoconjugates could maximize their efficacy and optimize their safety, extending their use in everyday clinical practice. Full article

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21 pages, 5349 KiB

Open AccessArticle

Human Transbodies to Reverse Transcriptase Connection Subdomain of HIV-1 Gag-Pol Polyprotein Reduce Infectiousness of the Virus Progeny

by Watee Seesuay, Siratcha Phanthong, Jaslan Densumite, Kodchakorn Mahasongkram, Nitat Sookrung and Wanpen Chaicumpa

Vaccines 2021, 9(8), 893; https://doi.org/10.3390/vaccines9080893 - 12 Aug 2021

Cited by 6 | Viewed by 2568

Abstract

HIV-1 progeny are released from infected cells as immature particles that are unable to infect new cells. Gag-Pol polyprotein dimerization via the reverse transcriptase connection domain (RTCDs) is pivotal for proper activation of the virus protease (PR protein) in an early event of [...] Read more.

HIV-1 progeny are released from infected cells as immature particles that are unable to infect new cells. Gag-Pol polyprotein dimerization via the reverse transcriptase connection domain (RTCDs) is pivotal for proper activation of the virus protease (PR protein) in an early event of the progeny virus maturation process. Thus, the RTCD is a potential therapeutic target for a broadly effective anti-HIV agent through impediment of virus maturation. In this study, human single-chain antibodies (HuscFvs) that bound to HIV-1 RTCD were generated using phage display technology. Computerized simulation guided the selection of the transformed Escherichia coli-derived HuscFvs that bound to the RTCD dimer interface. The selected HuscFvs were linked molecularly to human-derived-cell-penetrating peptide (CPP) to make them cell-penetrable (i.e., become transbodies). The CPP-HuscFvs/transbodies produced by a selected transformed E. coli clone were tested for anti-HIV-1 activity. CPP-HuscFvs of transformed E. coli clone 11 (CPP-HuscFv11) that presumptively bound at the RTCD dimer interface effectively reduced reverse transcriptase activity in the newly released virus progeny. Infectiousness of the progeny viruses obtained from CPP-HuscFv11-treated cells were reduced by a similar magnitude to those obtained from protease/reverse transcriptase inhibitor-treated cells, indicating anti-HIV-1 activity of the transbodies. The CPP-HuscFv11/transbodies to HIV-1 RTCD could be an alternative, anti-retroviral agent for long-term HIV-1 treatment. Full article

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14 pages, 4787 KiB

Open AccessArticle

Anti-CD47 Monoclonal Antibody–Drug Conjugate: A Targeted Therapy to Treat Triple-Negative Breast Cancers

by Yingnan Si, Ya Zhang, Jia-Shiung Guan, Hanh Giai Ngo, Angela Totoro, Ajeet Pal Singh, Kai Chen, Yuanxin Xu, Eddy S. Yang, Lufang Zhou, Runhua Liu and Xiaoguang (Margaret) Liu

Vaccines 2021, 9(8), 882; https://doi.org/10.3390/vaccines9080882 - 10 Aug 2021

Cited by 19 | Viewed by 7112

Abstract

Triple-negative breast cancers (TNBCs) are frequently recurrent due to the development of drug resistance post chemotherapy. Both the existing literature and our study found that surface receptor CD47 (cluster of differentiation 47) was upregulated in chemotherapy-treated TNBC cells. The goal of this study [...] Read more.

Triple-negative breast cancers (TNBCs) are frequently recurrent due to the development of drug resistance post chemotherapy. Both the existing literature and our study found that surface receptor CD47 (cluster of differentiation 47) was upregulated in chemotherapy-treated TNBC cells. The goal of this study was to develop a monoclonal antibody (mAb)-based targeting strategy to treat TNBC after standard treatment. Specifically, a new mAb that targets the extracellular domain of receptor CD47 was developed using hybridoma technology and produced in fed-batch culture. Flow cytometry, confocal microscopy, and in vivo imaging system (IVIS) showed that the anti-CD47 mAb effectively targeted human and mouse TNBC cells and xenograft models with high specificity. The antibody–drug conjugate (ADC) carrying mertansine was constructed and demonstrated higher potency with reduced IC₅₀ in TNBC cells than did the free drug and significantly inhibited tumor growth post gemcitabine treatment in MDA-MB-231 xenograft NSG model. Finally, whole blood analysis indicated that the anti-CD47 mAb had no general immune toxicity, flow cytometry analysis of lymph nodes revealed an increase of CD69⁺ NK, CD11c⁺ DC, and CD4⁺ T cells, and IHC staining showed tumoral infiltration of macrophage in the 4T1 xenograft BALB/cJ model. This study demonstrated that targeting CD47 with ADC has great potential to treat TNBCs as a targeted therapy. Full article

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11 pages, 3057 KiB

Open AccessArticle

Rabbit Monoclonal Antibody Specifically Recognizing a Linear Epitope in the RBD of SARS-CoV-2 Spike Protein

by Junping Hong, Qian Wang, Qian Wu, Junyu Chen, Xijing Wang, Yingbin Wang, Yixin Chen and Ningshao Xia

Vaccines 2021, 9(8), 829; https://doi.org/10.3390/vaccines9080829 - 28 Jul 2021

Cited by 9 | Viewed by 3560

Abstract

To date, SARS-CoV-2 pandemic has caused more than 188 million infections and 4.06 million deaths worldwide. The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein has been regarded as an important target for vaccine and therapeutics development because it plays a key role [...] Read more.

To date, SARS-CoV-2 pandemic has caused more than 188 million infections and 4.06 million deaths worldwide. The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein has been regarded as an important target for vaccine and therapeutics development because it plays a key role in binding the human cell receptor ACE2 that is required for viral entry. However, it is not easy to detect RBD in Western blot using polyclonal antibody, suggesting that RBD may form a complicated conformation under native condition and bear rare linear epitope. So far, no linear epitope on RBD is reported. Thus, a monoclonal antibody (mAb) that recognizes linear epitope on RBD will become valuable. In the present study, an RBD-specific rabbit antibody named 9E1 was isolated from peripheral blood mononuclear cells (PBMC) of immunized rabbit by RBD-specific single B cell sorting and mapped to a highly conserved linear epitope within twelve amino acids ⁴⁸⁰CNGVEGFNCYFP⁴⁹¹ on RBD. 9E1 works well in Western blot on S protein and immunohistochemistry on the SARS-CoV-2 infected tissue sections. The results demonstrated that 9E1 can be used as a useful tool for pathological and functional studies of SARS-CoV-2. Full article

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11 pages, 780 KiB

Open AccessReview

Detection of Urinary Antibodies and Its Application in Epidemiological Studies for Parasitic Diseases

by Fumiaki Nagaoka, Tatsuya Yamazaki, Sachiko Akashi-Takamura and Makoto Itoh

Vaccines 2021, 9(7), 778; https://doi.org/10.3390/vaccines9070778 - 12 Jul 2021

Cited by 7 | Viewed by 4348

Abstract

For epidemiological studies of infectious diseases, pathogen-specific antibody levels in an area give us essential and appropriate information. The antibodies against pathogens are usually detected in blood, the drawing of which inconveniences people. Collection of blood increases the risk of accidental infections through [...] Read more.

For epidemiological studies of infectious diseases, pathogen-specific antibody levels in an area give us essential and appropriate information. The antibodies against pathogens are usually detected in blood, the drawing of which inconveniences people. Collection of blood increases the risk of accidental infections through blood, and it is difficult to obtain the participation of the target populations, especially the younger generation. On the other hand, urine samples, which contain a high enough level of antibodies for ELISA, can be harmlessly and easily collected and therefore have been used for epidemiological studies for diseases. The antibody examination of urine has been used for the epidemiology of parasitic diseases with a high sensitivity and specificity of serum samples. In this paper, we reviewed antibody assays with urine for seven parasitic diseases that urine diagnostic methods have reported in the past, and these are important infections included in NTDs, caused, for example, by Leishmania donovani, Wuchereria bancrofti, Schistosoma japonicum, Paragonimus westermani, Echinococcus granulosus, Echinococcus multilocularis, Strongyloides stercoralis, and Opisthorchis viverrini. The easy and safe urine surveillance system might be an admirable tool for future epidemiological studies for infectious diseases. Full article

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12 pages, 3074 KiB

Open AccessArticle

Epitope–Paratope Interaction of a Neutralizing Human Anti-Hepatitis B Virus PreS1 Antibody That Recognizes the Receptor-Binding Motif

by Jisu Hong, Youngjin Choi, Yoonjoo Choi, Jiwoo Lee and Hyo Jeong Hong

Vaccines 2021, 9(7), 754; https://doi.org/10.3390/vaccines9070754 - 7 Jul 2021

Viewed by 3186

Abstract

Hepatitis B virus (HBV) is a global health burden that causes acute and chronic hepatitis. To develop an HBV-neutralizing antibody that effectively prevents HBV infection, we previously generated a human anti-preS1 monoclonal antibody (1A8) that binds to genotypes A–D and validated its HBV-neutralizing [...] Read more.

Hepatitis B virus (HBV) is a global health burden that causes acute and chronic hepatitis. To develop an HBV-neutralizing antibody that effectively prevents HBV infection, we previously generated a human anti-preS1 monoclonal antibody (1A8) that binds to genotypes A–D and validated its HBV-neutralizing activity in vitro. In the present study, we aimed to determine the fine epitope and paratope of 1A8 to understand the mechanism of HBV neutralization. We performed alanine-scanning mutagenesis on the preS1 (aa 19–34, genotype C) and the heavy (HCDR) and light (LCDR) chain complementarity-determining regions. The 1A8 recognized the three residues (Leu22, Gly23, and Phe25) within the highly conserved receptor-binding motif (NPLGFFP) of the preS1, while four CDR residues of 1A8 were critical in antigen binding. Structural analysis of the epitope–paratope interaction by molecular modeling revealed that Leu100 in the HCDR3, Ala50 in the HCDR2, and Tyr96 in the LCDR3 closely interacted with Leu22, Gly23, and Phe25 of the preS1. Additionally, we found that 1A8 also binds to the receptor-binding motif (NPLGFLP) of infrequently occurring HBV. The results suggest that 1A8 may broadly and effectively block HBV entry and thus have potential as a promising candidate for the prevention and treatment of HBV infection. Full article

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33 pages, 4007 KiB

Open AccessReview

Therapeutic Potential of HLA-I Polyreactive mAbs Mimicking the HLA-I Polyreactivity and Immunoregulatory Functions of IVIg

by Mepur H. Ravindranath, Fatiha El Hilali and Edward J. Filippone

Vaccines 2021, 9(6), 680; https://doi.org/10.3390/vaccines9060680 - 21 Jun 2021

Cited by 2 | Viewed by 3190

Abstract

HLA class-I (HLA-I) polyreactive monoclonal antibodies (mAbs) reacting to all HLA-I alleles were developed by immunizing mice with HLA-E monomeric, α-heavy chain (αHC) open conformers (OCs). Two mAbs (TFL-006 and TFL-007) were bound to the αHC’s coated on a solid matrix. The binding [...] Read more.

HLA class-I (HLA-I) polyreactive monoclonal antibodies (mAbs) reacting to all HLA-I alleles were developed by immunizing mice with HLA-E monomeric, α-heavy chain (αHC) open conformers (OCs). Two mAbs (TFL-006 and TFL-007) were bound to the αHC’s coated on a solid matrix. The binding was inhibited by the peptide ¹¹⁷AYDGKDY¹²³, present in all alleles of the six HLA-I isoforms but masked by β2-microglobulin (β2-m) in intact HLA-I trimers (closed conformers, CCs). IVIg preparations administered to lower anti-HLA Abs in pre-and post-transplant patients have also shown HLA-I polyreactivity. We hypothesized that the mAbs that mimic IVIg HLA-I polyreactivity might also possess the immunomodulatory capabilities of IVIg. We tested the relative binding affinities of the mAbs and IVIg for both OCs and CCs and compared their effects on (a) the phytohemagglutinin (PHA)-activation T-cells; (b) the production of anti-HLA-II antibody (Ab) by B-memory cells and anti-HLA-I Ab by immortalized B-cells; and (c) the upregulation of CD4+, CD25+, and Fox P³+ T-regs. The mAbs bound only to OC, whereas IVIg bound to both CC and OC. The mAbs suppressed blastogenesis and proliferation of PHA-activated T-cells and anti-HLA Ab production by B-cells and expanded T-regs better than IVIg. We conclude that a humanized version of the TFL-mAbs could be an ideal, therapeutic IVIg-mimetic. Full article

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17 pages, 2172 KiB

Open AccessReview

The Relevance of Monoclonal Antibodies in the Treatment of COVID-19

by Anabel Torrente-López, Jesús Hermosilla, Natalia Navas, Luis Cuadros-Rodríguez, José Cabeza and Antonio Salmerón-García

Vaccines 2021, 9(6), 557; https://doi.org/10.3390/vaccines9060557 - 26 May 2021

Cited by 8 | Viewed by 7391

Abstract

Major efforts have been made in the search for effective treatments since the outbreak of the COVID-19 infection in December 2019. Extensive research has been conducted on drugs that are already available and new treatments are also under development. Within this context, therapeutic [...] Read more.

Major efforts have been made in the search for effective treatments since the outbreak of the COVID-19 infection in December 2019. Extensive research has been conducted on drugs that are already available and new treatments are also under development. Within this context, therapeutic monoclonal antibodies (mAbs) have been the subject of widespread investigation focusing on two target-based groups, i.e., non-SARS-CoV-2 specific mAbs, that target immune system responses, and SARS-CoV-2 specific mAbs, designed to neutralize the virus protein structure. Here we review the latest literature about the use of mAbs in order to describe the state of the art of the clinical trials and the benefits of using these biotherapeutics in the treatment of COVID-19. The clinical trials considered in the present review include both observational and randomized studies. We begin by presenting the studies conducted using non-SARS-CoV-2 specific mAbs for treating different immune disorders that were already on the market. Within this group of mAbs, we focus particularly on anti-IL-6/IL-6R. This is followed by a discussion of the studies on SARS-CoV-2 specific mAbs. Our findings indicate that SARS-CoV-2 specific mAbs are significantly more effective than non-specific ones. Full article

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17 pages, 921 KiB

Open AccessReview

Monoclonal Antibodies Targeting Surface-Exposed and Secreted Proteins from Staphylococci

by Pietro Speziale and Giampiero Pietrocola

Vaccines 2021, 9(5), 459; https://doi.org/10.3390/vaccines9050459 - 4 May 2021

Cited by 13 | Viewed by 4327

Abstract

Staphylococci (specifically Staphylococcus aureus and Staphylococcus epidermidis) are the causative agents of diseases ranging from superficial skin and soft tissue infections to severe conditions such as fatal pneumonia, bacteremia, sepsis and endocarditis. The widespread and indiscriminate use of antibiotics has led to [...] Read more.

Staphylococci (specifically Staphylococcus aureus and Staphylococcus epidermidis) are the causative agents of diseases ranging from superficial skin and soft tissue infections to severe conditions such as fatal pneumonia, bacteremia, sepsis and endocarditis. The widespread and indiscriminate use of antibiotics has led to serious problems of resistance to staphylococcal disease and has generated a renewed interest in alternative therapeutic agents such as vaccines and antibodies. Staphylococci express a large repertoire of surface and secreted virulence factors, which provide mechanisms (adhesion, invasion and biofilm development among others) for both bacterial survival in the host and evasion from innate and adaptive immunity. Consequently, the development of antibodies that target specific antigens would provide an effective protective strategy against staphylococcal infections. In this review, we report an update on efforts to develop anti-staphylococci monoclonal antibodies (and their derivatives: minibodies, antibody–antibiotic conjugates) and the mechanism by which such antibodies can help fight infections. We also provide an overview of mAbs used in clinical trials and highlight their therapeutic potential in various infectious contexts. Full article

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19 pages, 3150 KiB

Open AccessArticle

Engineered Human Monoclonal scFv to Receptor Binding Domain of Ebolavirus

by Jaslan Densumite, Siratcha Phanthong, Watee Seesuay, Nitat Sookrung, Urai Chaisri and Wanpen Chaicumpa

Vaccines 2021, 9(5), 457; https://doi.org/10.3390/vaccines9050457 - 4 May 2021

Cited by 4 | Viewed by 2751

Abstract

(1) Background: Ebolavirus (EBOV) poses as a significant threat for human health by frequently causing epidemics of the highly contagious Ebola virus disease (EVD). EBOV glycoprotein (GP), as a sole surface glycoprotein, needs to be cleaved in endosomes to fully expose a receptor-binding [...] Read more.

(1) Background: Ebolavirus (EBOV) poses as a significant threat for human health by frequently causing epidemics of the highly contagious Ebola virus disease (EVD). EBOV glycoprotein (GP), as a sole surface glycoprotein, needs to be cleaved in endosomes to fully expose a receptor-binding domain (RBD) containing a receptor-binding site (RBS) for receptor binding and genome entry into cytoplasm for replication. RBDs are highly conserved among EBOV species, so they are an attractive target for broadly effective anti-EBOV drug development. (2) Methods: Phage display technology was used as a tool to isolate human single-chain antibodies (HuscFv) that bind to recombinant RBDs from a human scFv (HuscFv) phage display library. The RBD-bound HuscFvs were fused with cell-penetrating peptide (CPP), and cell-penetrating antibodies (transbodies) were made, produced from the phage-infected E. coli clones and characterized. (3) Results: Among the HuscFvs obtained from phage-infected E. coli clones, HuscFvs of three clones, HuscFv4, HuscFv11, and HuscFv14, the non-cell-penetrable or cell-penetrable HuscFv4 effectively neutralized cellular entry of EBOV-like particles (VLPs). While all HuscFvs were found to bind cleaved GP (GPcl), their presumptive binding sites were markedly different, as determined by molecular docking. (4) Conclusions: The HuscFv4 could be a promising therapeutic agent against EBOV infection. Full article

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14 pages, 1642 KiB

Open AccessArticle

Passive Immunity and Antibody Response Induced by Toxoplasma gondii VLP Immunization

by Hae-Ji Kang, Min-Ju Kim, Ki-Back Chu, Su-Hwa Lee, Eun-Kyung Moon and Fu-Shi Quan

Vaccines 2021, 9(5), 425; https://doi.org/10.3390/vaccines9050425 - 23 Apr 2021

Cited by 3 | Viewed by 3285

Abstract

Passive immunity can provide immediate protection against infectious pathogens. To date, only a few studies have investigated the effect of passive immunization against Toxoplasma gondii, and the use of immune sera acquired from VLP-vaccinated mice for passive immunity assessment remains unreported. In [...] Read more.

Passive immunity can provide immediate protection against infectious pathogens. To date, only a few studies have investigated the effect of passive immunization against Toxoplasma gondii, and the use of immune sera acquired from VLP-vaccinated mice for passive immunity assessment remains unreported. In this study, immune sera were produced by a single immunization with virus-like particles (VLPs) expressing the inner membrane complex (IMC), rhoptry protein 18 (ROP18), and microneme protein 8 (MIC8) of Toxoplasma gondii, with or without a CpG-ODN adjuvant. The passive immunization of immune sera conferred protection in mice, as indicated by their potent parasite-specific antibody response, lessened brain cyst counts, lower bodyweight loss, and enhanced survival. In order to confirm that the immune sera of the VLP-immunized mice were truly protective, the antibody responses and other immunological parameters were measured in the VLP-immunized mice. We found that VLP immunization induced higher levels of parasite-specific IgG, IgG subclass, and IgM antibody responses in the sera and intestines than in the controls. Enhanced Th1 and Th2-associated cytokines in the spleen, diminished brain cyst counts, and lessened body weight loss were found following T. gondii ME49 challenge infection. These results suggest that passive immunization with the immune sera acquired from VLP-vaccinated mice can confer adequate protection against T. gondii infection. Full article

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21 pages, 770 KiB

Open AccessReview

Therapeutic Antibodies for the Treatment of Respiratory Tract Infections—Current Overview and Perspectives

by Alexie Mayor, Adélaïde Chesnay, Guillaume Desoubeaux, David Ternant, Nathalie Heuzé-Vourc’h and Thomas Sécher

Vaccines 2021, 9(2), 151; https://doi.org/10.3390/vaccines9020151 - 13 Feb 2021

Cited by 5 | Viewed by 5182

Abstract

Respiratorytract infections (RTIs) are frequent and life-threatening diseases, accounting for several millions of deaths worldwide. RTIs implicate microorganisms, including viruses (influenza virus, coronavirus, respiratory syncytial virus (RSV)), bacteria (Pseudomonas aeruginosa, Streptococcus pneumoniae, Staphylococcus aureus and Bacillus anthracis) and fungi [...] Read more.

Respiratorytract infections (RTIs) are frequent and life-threatening diseases, accounting for several millions of deaths worldwide. RTIs implicate microorganisms, including viruses (influenza virus, coronavirus, respiratory syncytial virus (RSV)), bacteria (Pseudomonas aeruginosa, Streptococcus pneumoniae, Staphylococcus aureus and Bacillus anthracis) and fungi (Pneumocystis spp., Aspergillus spp. and very occasionally Candida spp.). The emergence of new pathogens, like the coronavirus SARS-CoV-2, and the substantial increase in drug resistance have highlighted the critical necessity to develop novel anti-infective molecules. In this context, antibodies (Abs) are becoming increasingly important in respiratory medicine and may fulfill the unmet medical needs of RTIs. However, development of Abs for treating infectious diseases is less advanced than for cancer and inflammatory diseases. Currently, only three Abs have been marketed for RTIs, namely, against pulmonary anthrax and RSV infection, while several clinical and preclinical studies are in progress. This article gives an overview of the advances in the use of Abs for the treatment of RTIs, based on the analysis of clinical studies in this field. It describes the Ab structure, function and pharmacokinetics, and discusses the opportunities offered by the various Ab formats, Ab engineering and co-treatment strategies. Including the most recent literature, it finally highlights the strengths, weaknesses and likely future trends of a novel anti-RTI Ab armamentarium. Full article

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12 pages, 2689 KiB

Open AccessArticle

Identification of Two Novel Linear Neutralizing Epitopes within the Hexon Protein of Canine Adenovirus Using Monoclonal Antibodies

by Shujie Wang, Chunsheng Wang, Xiao Ren, Wenjiao Xue, Haijuan He, Yanzhu Zhu, Hongfeng Wang, Gang Wang and Xuehui Cai

Vaccines 2021, 9(2), 135; https://doi.org/10.3390/vaccines9020135 - 8 Feb 2021

Cited by 3 | Viewed by 2977

Abstract

Canine adenovirus (CAdV) has a high prevalence in canine populations. High affinity neutralizing antibodies against conserved epitopes can provide protective immunity against CAdV and protect against future outbreaks. In this study, we identified two CAdV-2-specific neutralizing monoclonal antibodies (mAbs), 2C1 and 7D7, which [...] Read more.

Canine adenovirus (CAdV) has a high prevalence in canine populations. High affinity neutralizing antibodies against conserved epitopes can provide protective immunity against CAdV and protect against future outbreaks. In this study, we identified two CAdV-2-specific neutralizing monoclonal antibodies (mAbs), 2C1 and 7D7, which recognized two linear-dependent epitopes. MAb 2C1 potently neutralized CAdV-2 with a 50% neutralization titer (NT50) of 4096, and mAb 7D7 partially neutralized CAdV-2 with a 50% NT50 of 64. Immunoprecipitation, Western blot and protein spectral analysis indicated that both neutralizing mAbs recognized the hexon protein (Hex) of CAdV-2. Through a 12-mer random peptide phage display and synthetic peptides analysis, we finely mapped the neutralizing epitopes to two 10-amino acid (aa) peptides within the CAdV Hex: ⁶³⁴RIKQRETPAL⁶⁴³ located on the surface region; and ⁷³⁶PESYKDRMYS⁷⁴⁵ located in the inner region of the expected 3D structure of trimeric Hex. Importantly, the two epitopes are highly conserved among all CAdV isolates by sequence alignment analysis. Thus, these results provide insights into the interaction between virus and mAbs at the aa level and may have potential applications in the development of novel therapeutic or epitope-based vaccines, antibody therapeutics and a diagnostic method suitable for the rapid detection of all CAdVs. Full article

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2020

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20 pages, 5214 KiB

Open AccessArticle

Dissecting the NK Cell Population in Hematological Cancers Confirms the Presence of Tumor Cells and Their Impact on NK Population Function

by Dang-Nghiem Vo, Michael Constantinides, Nerea Allende-Vega, Catherine Alexia, Guillaume Cartron and Martin Villalba

Vaccines 2020, 8(4), 727; https://doi.org/10.3390/vaccines8040727 - 2 Dec 2020

Cited by 8 | Viewed by 3164

Abstract

The lymphocyte lineage natural killer (NK) cell is part of the innate immune system and protects against pathogens and tumor cells. NK cells are the main cell effectors of the monoclonal antibodies (mAbs) that mediates antibody-dependent cell cytotoxicity (ADCC). Hence, it is relevant [...] Read more.

The lymphocyte lineage natural killer (NK) cell is part of the innate immune system and protects against pathogens and tumor cells. NK cells are the main cell effectors of the monoclonal antibodies (mAbs) that mediates antibody-dependent cell cytotoxicity (ADCC). Hence, it is relevant to understand NK physiology and status to investigate the biological effect of mAbs in the clinic. NK cells are heterogeneous with multiple subsets that may have specific activity against different attacks. The presence of viral-sculpted NK cell populations has already been described, but the presence of cancer-sculpted NK cells remains unknown. Cancer induces a broad NK cell dysfunction, which has not been linked to a specific population. Here, we investigated the NK cell population by Uniform Manifold Approximation and Projection (UMAP) embed maps in Hodgkin lymphoma (HL) and acute myeloid leukemia (AML) patients at diagnosis and at least 30 days after treatment, which correlates with tumor cell clearance. We found that the NK lineage largely responded to the tumor by generating antitumor NK cells and renewing the population with a subset of immature NK cells. However, we failed to identify a specific “memory-like” subset with the NK cell markers used. Moreover, in patients in relapse, we found essentially the same NK populations as those found at diagnosis, suggesting that NK cells equally respond to the first or second tumor rise. Finally, we observed that previous cytomegalovirus (CMV) infection largely affects the tumor-associated changes in NK population, but the CMV-associated CD57⁺NKG2C⁺ NK cell population does not appear to play any role in tumor immunity. Full article

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