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Rahman MA, Becerra-Flores M, Patskovsky Y, Silva de Castro I, Bissa M, Basu S, Shen X, Williams LD, Sarkis S, N’guessan KF, LaBranche C, Tomaras GD, Aye PP, Veazey R, Paquin-Proulx D, Rao M, Franchini G, Cardozo T. Cholera toxin B scaffolded, focused SIV V2 epitope elicits antibodies that influence the risk of SIV mac251 acquisition in macaques. Front Immunol 2023; 14:1139402. [PMID: 37153584 PMCID: PMC10160393 DOI: 10.3389/fimmu.2023.1139402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 03/30/2023] [Indexed: 05/09/2023] Open
Abstract
Introduction An efficacious HIV vaccine will need to elicit a complex package of innate, humoral, and cellular immune responses. This complex package of responses to vaccine candidates has been studied and yielded important results, yet it has been a recurring challenge to determine the magnitude and protective effect of specific in vivo immune responses in isolation. We therefore designed a single, viral-spike-apical, epitope-focused V2 loop immunogen to reveal individual vaccine-elicited immune factors that contribute to protection against HIV/SIV. Method We generated a novel vaccine by incorporating the V2 loop B-cell epitope in the cholera toxin B (CTB) scaffold and compared two new immunization regimens to a historically protective 'standard' vaccine regimen (SVR) consisting of 2xDNA prime boosted with 2xALVAC-SIV and 1xΔV1gp120. We immunized a cohort of macaques with 5xCTB-V2c vaccine+alum intramuscularly simultaneously with topical intrarectal vaccination of CTB-V2c vaccine without alum (5xCTB-V2/alum). In a second group, we tested a modified version of the SVR consisting of 2xDNA prime and boosted with 1xALVAC-SIV and 2xALVAC-SIV+CTB-V2/alum, (DA/CTB-V2c/alum). Results In the absence of any other anti-viral antibodies, V2c epitope was highly immunogenic when incorporated in the CTB scaffold and generated highly functional anti-V2c antibodies in the vaccinated animals. 5xCTB-V2c/alum vaccination mediated non-neutralizing ADCC activity and efferocytosis, but produced low avidity, trogocytosis, and no neutralization of tier 1 virus. Furthermore, DA/CTB-V2c/alum vaccination also generated lower total ADCC activity, avidity, and neutralization compared to the SVR. These data suggest that the ΔV1gp120 boost in the SVR yielded more favorable immune responses than its CTB-V2c counterpart. Vaccination with the SVR generates CCR5- α4β7+CD4+ Th1, Th2, and Th17 cells, which are less likely to be infected by SIV/HIV and likely contributed to the protection afforded in this regimen. The 5xCTB-V2c/alum regimen likewise elicited higher circulating CCR5- α4β7+ CD4+ T cells and mucosal α4β7+ CD4+ T cells compared to the DA/CTB-V2c/alum regimen, whereas the first cell type was associated with reduced risk of viral acquisition. Conclusion Taken together, these data suggest that individual viral spike B-cell epitopes can be highly immunogenic and functional as isolated immunogens, although they might not be sufficient on their own to provide full protection against HIV/SIV infection.
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Affiliation(s)
- Mohammad Arif Rahman
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, NIH Bethesda, MD, United States
| | - Manuel Becerra-Flores
- NYU Langone Health, New York University School of Medicine, New York, NY, United States
| | - Yury Patskovsky
- NYU Langone Health, New York University School of Medicine, New York, NY, United States
| | - Isabela Silva de Castro
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, NIH Bethesda, MD, United States
| | - Massimiliano Bissa
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, NIH Bethesda, MD, United States
| | - Shraddha Basu
- United States Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Xiaoying Shen
- Department of Surgery, Duke University School of Medicine, Durham, NC, United States
| | - LaTonya D. Williams
- Department of Surgery, Duke University School of Medicine, Durham, NC, United States
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, United States
| | - Sarkis Sarkis
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, NIH Bethesda, MD, United States
| | - Kombo F. N’guessan
- United States Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Celia LaBranche
- Department of Surgery, Duke University School of Medicine, Durham, NC, United States
| | - Georgia D. Tomaras
- Department of Surgery, Duke University School of Medicine, Durham, NC, United States
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, United States
| | - Pyone Pyone Aye
- Veterinary Medicine, Tulane National Primate Research Center, Covington, LA, United States
| | - Ronald Veazey
- Division of Comparative Pathology, Department of Pathology and Laboratory Medicine, Tulane National Primate Research Center, Tulane University School of Medicine, Covington, LA, United States
| | - Dominic Paquin-Proulx
- United States Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Mangala Rao
- United States Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Genoveffa Franchini
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, NIH Bethesda, MD, United States
| | - Timothy Cardozo
- NYU Langone Health, New York University School of Medicine, New York, NY, United States
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