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Wei J, Cheng X, Zhang Y, Gao C, Wang Y, Peng Q, Luo P, Yang L, Zou Q, Zeng H, Gu J. Identification and application of a neutralizing epitope within alpha-hemolysin using human serum antibodies elicited by vaccination. Mol Immunol 2021; 135:45-52. [PMID: 33873093 DOI: 10.1016/j.molimm.2021.03.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/08/2021] [Accepted: 03/31/2021] [Indexed: 11/15/2022]
Abstract
Staphylococcus aureus (SA), especially the methicillin-resistant variant (MRSA), is becoming a serious threat to human health in hospitals and communities, making the development of an effective vaccine urgent. Alpha-hemolysin (Hla) is a key virulence factor and also a good target for the development of SA vaccines. However, the epitopes in Hla recognized by human immunity are not characterized in detail, which hinders the design of epitope-based human vaccines against SA. In this study, we collected sera from volunteers in a phase 1b clinical trial of a novel recombinant five-antigen SA vaccine (NCT03966040). Using a Luminex-based assay, we characterized the human serologic response against Hla, and identified Hla121-138 as a neutralizing epitope. In addition, we successfully produced ferritin nanoparticles carrying the neutralizing Hla121-138 epitope (EpNP) in E. coli. EpNP presented as homogenous nanoparticles in aqueous solution. Immunization with EpNP elicited potent hemolysis-neutralizing antibodies and conferred significant protection in a mouse model of SA skin infection. Our data suggest that EpNP, carrying the neutralizing epitope Hla121-138, is a good candidate for a vaccine against SA.
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Affiliation(s)
- Jinning Wei
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing, 400038, PR China
| | - Xin Cheng
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing, 400038, PR China
| | - Yi Zhang
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing, 400038, PR China
| | - Chen Gao
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing, 400038, PR China
| | - Ying Wang
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing, 400038, PR China
| | - Qi Peng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Ping Luo
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing, 400038, PR China
| | - Liuyang Yang
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing, 400038, PR China; Medical Laboratory Center, First Medical Center of Chinese PLA General Hospital, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China
| | - Quanming Zou
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing, 400038, PR China
| | - Hao Zeng
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing, 400038, PR China.
| | - Jiang Gu
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing, 400038, PR China.
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Zeng H, Zhang J, Song X, Zeng J, Yuan Y, Chen Z, Xu L, Gou Q, Yang F, Zeng N, Zhang Y, Peng L, Zhao L, Zhu J, Liu Y, Luo P, Zou Q, Zhao Z. An Immunodominant Epitope-Specific Monoclonal Antibody Cocktail Improves Survival in a Mouse Model of Staphylococcus aureus Bacteremia. J Infect Dis 2020; 223:1743-1752. [PMID: 32959055 DOI: 10.1093/infdis/jiaa602] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 09/18/2020] [Indexed: 01/22/2023] Open
Abstract
To date, no vaccine or monoclonal antibody (mAb) against Staphylococcus aureus has been approved for use in humans. Our laboratory has developed a 5-antigen S. aureus vaccine (rFSAV), which is now under efficacy evaluation in a phase 2 clinical trial. In the current study, using overlapping peptides and antiserum from rFSAV-immunized volunteers, we identified 7 B-cell immunodominant epitopes on 4 antigens in rFSAV, including 5 novel epitopes (Hla48-65, IsdB402-419, IsdB432-449, SEB78-95, and MntC7-24). Ten immunodominant epitope mAbs were generated against these epitopes, and all of them exhibited partial protection in a mouse sepsis model. Four robust mAbs were used together as an mAb cocktail to prevent methicillin-resistant S. aureus strain 252 infection. The results showed that the mAb cocktail was efficient in combating S. aureus infection and that its protective efficacy correlated with a reduced bacterial burden and decreased infection pathology, which demonstrates that the mAb cocktail is a promising S. aureus vaccine candidate.
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Affiliation(s)
- Hao Zeng
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Jinyong Zhang
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Xu Song
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Jiangmin Zeng
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Yue Yuan
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Zhifu Chen
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Limin Xu
- Chengdu Olymvax Biotechnology Co, Ltd, Chengdu, Sichuan, People's Republic of China
| | - Qiang Gou
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Feng Yang
- Chengdu Olymvax Biotechnology Co, Ltd, Chengdu, Sichuan, People's Republic of China
| | - Ni Zeng
- Chengdu Olymvax Biotechnology Co, Ltd, Chengdu, Sichuan, People's Republic of China
| | - Yi Zhang
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Liusheng Peng
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Liqun Zhao
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Jiang Zhu
- Department of Pathology, Southwest Hospital, Army Medical University, Chongqing, People's Republic of China
| | - Yuanyuan Liu
- Medical Corps Department, Unit 69016, Chinese People's Liberation Army, Xinjiang, People's Republic of China
| | - Ping Luo
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Quanming Zou
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
| | - Zhuo Zhao
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing, People's Republic of China
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Vaccination with VLPs Presenting a Linear Neutralizing Domain of S. aureus Hla Elicits Protective Immunity. Toxins (Basel) 2020; 12:toxins12070450. [PMID: 32664481 PMCID: PMC7404987 DOI: 10.3390/toxins12070450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 01/14/2023] Open
Abstract
The pore-forming cytotoxin α-hemolysin, or Hla, is a critical Staphylococcus aureus virulence factor that promotes infection by causing tissue damage, excessive inflammation, and lysis of both innate and adaptive immune cells, among other cellular targets. In this study, we asked whether a virus-like particle (VLP)-based vaccine targeting Hla could attenuate S. aureus Hla-mediated pathogenesis. VLPs are versatile vaccine platforms that can be used to display target antigens in a multivalent array, typically resulting in the induction of high titer, long-lasting antibody responses. In the present study, we describe the first VLP-based vaccines that target Hla. Vaccination with either of two VLPs displaying a 21 amino-acid linear neutralizing domain (LND) of Hla protected both male and female mice from subcutaneous Hla challenge, evident by reduction in lesion size and neutrophil influx to the site of intoxication. Antibodies elicited by VLP-LND vaccination bound both the LND peptide and the native toxin, effectively neutralizing Hla and preventing toxin-mediated lysis of target cells. We anticipate these novel and promising vaccines being part of a multi-component S. aureus vaccine to reduce severity of S. aureus infection.
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Triplett KD, Pokhrel S, Castleman MJ, Daly SM, Elmore BO, Joyner JA, Sharma G, Herbert G, Campen MJ, Hathaway HJ, Prossnitz ER, Hall PR. GPER activation protects against epithelial barrier disruption by Staphylococcus aureus α-toxin. Sci Rep 2019; 9:1343. [PMID: 30718654 PMCID: PMC6362070 DOI: 10.1038/s41598-018-37951-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 12/07/2018] [Indexed: 02/07/2023] Open
Abstract
Sex bias in innate defense against Staphylococcus aureus skin and soft tissue infection (SSTI) is dependent on both estrogen production by the host and S. aureus secretion of the virulence factor, α-hemolysin (Hla). The impact of estrogen signaling on the immune system is most often studied in terms of the nuclear estrogen receptors ERα and ERβ. However, the potential contribution of the G protein-coupled estrogen receptor (GPER) to innate defense against infectious disease, particularly with respect to skin infection, has not been addressed. Using a murine model of SSTI, we found that GPER activation with the highly selective agonist G-1 limits S. aureus SSTI and Hla-mediated pathogenesis, effects that were absent in GPER knockout mice. Specifically, G-1 reduced Hla-mediated skin lesion formation and pro-inflammatory cytokine production, while increasing bacterial clearance. In vitro, G-1 reduced surface expression of the Hla receptor, ADAM10, in a human keratinocyte cell line and increased resistance to Hla-mediated permeability barrier disruption. This novel role for GPER activation in skin innate defense against infectious disease suggests that G-1 may have clinical utility in patients with epithelial permeability barrier dysfunction or who are otherwise at increased risk of S. aureus infection, including those with atopic dermatitis or cancer.
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Affiliation(s)
- Kathleen D Triplett
- University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM, 87131, USA
| | - Srijana Pokhrel
- University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM, 87131, USA
| | - Moriah J Castleman
- University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM, 87131, USA
| | - Seth M Daly
- University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM, 87131, USA
| | - Bradley O Elmore
- University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM, 87131, USA
| | - Jason A Joyner
- University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM, 87131, USA
| | - Geetanjali Sharma
- University of New Mexico School of Medicine, Department of Internal Medicine, Albuquerque, NM, 87131, USA
| | - Guy Herbert
- University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM, 87131, USA
| | - Matthew J Campen
- University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM, 87131, USA
| | - Helen J Hathaway
- University of New Mexico School of Medicine, Department of Cell Biology & Physiology, Albuquerque, NM, 87131, USA
| | - Eric R Prossnitz
- University of New Mexico School of Medicine, Department of Internal Medicine, Albuquerque, NM, 87131, USA
| | - Pamela R Hall
- University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM, 87131, USA.
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VLP-based vaccine induces immune control of Staphylococcus aureus virulence regulation. Sci Rep 2017; 7:637. [PMID: 28377579 PMCID: PMC5429642 DOI: 10.1038/s41598-017-00753-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/09/2017] [Indexed: 12/12/2022] Open
Abstract
Staphylococcus aureus is the leading cause of skin and soft tissue infections (SSTIs) and mounting antibiotic resistance requires innovative treatment strategies. S. aureus uses secreted cyclic autoinducing peptides (AIPs) and the accessory gene regulator (agr) operon to coordinate expression of virulence factors required for invasive infection. Of the four agr alleles (agr types I-IV and corresponding AIPs1-4), agr type I isolates are most frequently associated with invasive infection. Cyclization via a thiolactone bond is essential for AIP function; therefore, recognition of the cyclic form of AIP1 may be necessary for antibody-mediated neutralization. However, the small sizes of AIPs and labile thiolactone bond have hindered vaccine development. To overcome this, we used a virus-like particle (VLP) vaccine platform (PP7) for conformationally-restricted presentation of a modified AIP1 amino acid sequence (AIP1S). Vaccination with PP7-AIP1S elicited AIP1-specific antibodies and limited agr-activation in vivo. Importantly, in a murine SSTI challenge model with a highly virulent agr type I S. aureus isolate, PP7-AIP1S vaccination reduced pathogenesis and increased bacterial clearance compared to controls, demonstrating vaccine efficacy. Given the contribution of MRSA agr type I isolates to human disease, vaccine targeting of AIP1-regulated virulence could have a major clinical impact in the fight against antibiotic resistance.
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Abstract
Traditional vaccination with whole pathogens or pathogen-derived subunits has completely eliminated diseases like smallpox, and has greatly limited the incidence, morbidity and mortality associated with many other infectious diseases. Unfortunately, a large burden of infectious disease remains that may be preventable through vaccination. For many of these, more focused and innovative approaches may be essential for the development of effective vaccines.
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Affiliation(s)
- Jon Oscherwitz
- a Division of Hematology-Oncology, Department of Internal Medicine , University of Michigan Medical School , Ann Arbor , MI , USA.,b Veterans Administration Ann Arbor Healthcare System , Ann Arbor , MI , USA
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Ahmad TA, Eweida AE, Sheweita SA. B-cell epitope mapping for the design of vaccines and effective diagnostics. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.trivac.2016.04.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Oscherwitz J, Cease KB. Identification and validation of a linear protective neutralizing epitope in the β-pore domain of alpha toxin. PLoS One 2015; 10:e0116882. [PMID: 25635901 PMCID: PMC4311967 DOI: 10.1371/journal.pone.0116882] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 12/16/2014] [Indexed: 02/07/2023] Open
Abstract
The plethora of virulence factors associated with Staphylococcus aureus make this bacterium an attractive candidate for a molecularly-designed epitope-focused vaccine. This approach, which necessitates the identification of neutralizing epitopes for incorporation into a vaccine construct, is being evaluated for pathogens where conventional approaches have failed to elicit protective humoral responses, like HIV-1 and malaria, but may also hold promise for pathogens like S. aureus, where the elicitation of humoral immunity against multiple virulence factors may be required for development of an effective vaccine. Among the virulence factors employed by S. aureus, animal model and epidemiological data suggest that alpha toxin, a multimeric β-pore forming toxin like protective antigen from Bacillus anthracis, is particularly critical, yet no candidate neutralizing epitopes have been delineated in alpha toxin to date. We have previously shown that a linear determinant in the 2β2-2β3 loop of the pore forming domain of B. anthracis protective antigen is a linear neutralizing epitope. Antibody against this site is highly potent for neutralizing anthrax lethal toxin in vitro and for protection of rabbits in vivo from virulent B. anthracis. We hypothesized that sequences in the β-pore of S. aureus alpha toxin that share structural and functional homology to β-pore sequences in protective antigen would contain a similarly critical neutralizing epitope. Using an in vivo mapping strategy employing peptide immunogens, an optimized in vitro toxin neutralization assay, and an in vivo dermonecrosis model, we have now confirmed the presence of this epitope in alpha toxin, termed the pore neutralizing determinant. Antibody specific for this determinant neutralizes alpha toxin in vitro, and is highly effective for mitigating dermonecrosis and bacterial growth in a mouse model of S. aureus USA300 skin infection. The delineation of this linear neutralizing determinant in alpha toxin could facilitate the development of an epitope-focused vaccine against S. aureus.
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Affiliation(s)
- Jon Oscherwitz
- Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, 48105, United States of America; VA Ann Arbor Healthcare System, 2215 Fuller Road, Ann Arbor, Michigan, 48105, United States of America
| | - Kemp B Cease
- Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, 48105, United States of America; VA Ann Arbor Healthcare System, 2215 Fuller Road, Ann Arbor, Michigan, 48105, United States of America
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