Figure 4
Comparison of Ab responses to V1V2 and V3 in males and females at peak vs final time points. Plasma samples from 11 male and 12 female VAX003 vaccinees and 12 male and 11 female VAX004 vaccinees were tested at 1:100 dilution for ELISA IgG reactivity against V1V2-gp70 (B.Case A2), V1V2-tags (C.1086), Cyc V2 peptides (AE.92TH023 or B.MN), full-length V3 (B.MN), V3 cradle, and V3 ladle. Samples from A02 visit (prebleed) and 2 weeks after each vaccination (visits A03-A15) were tested. Each sample was tested in 2 to 4 replicates in 1 or 2 independent experiments. (a) Changes of Ab levels from peak (A07 or A09) vs final (A15) time points were evaluated for male vs female vaccinees by paired, 2-tailed t test. Percentages of responders at peak were also calculated. (b) Representative graphs show declining Ab responses to V1V2 and V3 in male but not in female participants of the VAX004 study. Average Ab levels are highlighted by bold blue lines. Cutoff values (dotted lines) were based on mean and 3 standard deviations of placebo recipients. Comparison of Ab strength between A15 (final) and A07 or A09 (peak) was done by t test (paired, 2 tailed). *P < 0.05, **P < 0.01, ***P < 0.001, NS: not significant (P ≥ 0.05). OD405, optical density at 405 nm.
