Retrospective analysis of sex-disaggregated immune responses to ALVAC-HIV and bivalent subtype C gp120/MF59 HIV vaccines

IntroductionGenerally, individuals assigned female at birth (AFAB) develop greater immunogenicity to various vaccines than individuals assigned male at birth (AMAB). Little is known about sex-disaggregated immunogenicity to HIV-1 vaccines. We disaggregated immune responses to an experimental HIV vac...

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Main Authors: Cassie G. Ackerley, Srilatha Edupuganti, Chenchen Yu, Alison C. Roxby, Kelly E. Seaton, Linda-Gail Bekker, Mary Allen, Stephen C. DeRosa, Nicole L. Yates, Jack Heptinstall, Nonhlanhla N. Mkhize, Mookho Malahleha, Kathryn Mngadi, Brodie Daniels, Craig Innes, Briana D. Furch, Marguerite Koutsoukos, Guido Ferrari, Lynn Morris, David C. Montefiori, M. Juliana McElrath, Georgia D. Tomaras, Fatima Laher, Zoe Moodie
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-05-01
Series:Frontiers in Immunology
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Online Access:https://www.frontiersin.org/articles/10.3389/fimmu.2025.1557009/full
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Summary:IntroductionGenerally, individuals assigned female at birth (AFAB) develop greater immunogenicity to various vaccines than individuals assigned male at birth (AMAB). Little is known about sex-disaggregated immunogenicity to HIV-1 vaccines. We disaggregated immune responses to an experimental HIV vaccine regimen.MethodsWe retrospectively analyzed data from HVTN 100, a clinical trial conducted in South Africa during which 143 adults AMAB and 109 AFAB aged 18–40 years without HIV received ALVAC-HIV vCP2438 plus bivalent subtype C gp120/MF59 or placebo at 0, 1, 3, 6, and 12 months. Eligible data were from per-protocol vaccine recipients at month 6.5. We measured IgG binding antibodies, neutralizing antibodies, antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and CD4+ IFNγ and/or II-2 responses. We compared sex-based differences in response rates using Barnard’s test and response magnitudes using Wilcoxon Rank Sum test. P-values were Holm-adjusted for multiple comparisons.ResultsOf 185 vaccine recipients, 73 were AFAB and 112 were AMAB. Vaccine recipients AFAB had greater ADCC response rate (57.5% versus 29.5%; padj = 0.0003) and greater ADCC magnitude (area under the net % granzyme B activity vs log10 curve (AUC), 16.1 versus 11.2; padj = 0.05) to vaccine-matched antigen TV1.C gp120 compared to AMAB. Vaccine recipients AMAB had higher CD4+ T cell response rates to 2/3 vaccine-matched antigens at month 6.5 (ZM96.C gp120, [54.1% versus 36.8%; padj = 0.04]; 1086.C gp120, [44.1% versus 29.4%; padj = 0.05]) than AFAB. CD4+ T cell response magnitudes were similar by sex. IgG binding antibody response rate to B.CaseA V1V2 antigen (associated with reduced HIV acquisition risk in the RV144 trial) was 56.8% among AMAB vaccine recipients versus 38.9% among AFAB (padj = 0.08). There were no sex-based differences in neutralizing antibody or ADCP responses.DiscussionWe identified sex-based differences in immune responses to an HIV vaccine regimen, but they varied by immunologic assay. While vaccine recipients AFAB demonstrated higher ADCC responses, AMAB exhibited higher CD4+ T cell response rates. Future analyses should investigate whether vaccine factors such as platform, dosing and adjuvants contribute to sex-based differences in immunogenicity of experimental HIV vaccines.
ISSN:1664-3224