Fig. 5: Heterologous Env vaccination boosts pre-existing autologous Env-specific B cell responses compared to vaccine-specific responses among vaccinated RMs- evidence for antigenic seniority.

IgG binding responses specific for vaccine and challenge virus antigens were compared among Env vaccinated RMs (a). To evaluate changes in IgG binding responses among the vaccinated cohort across all three antigens, the fold change (b) from week 12 (pre-ART/immunization) were compared for each antigen at 16, 20, and 24 wpi (2 weeks post each immunization). Antibody avidity, measured by SPR, across all three antigens were also compared among vaccinees (c). Frequency of CH505 and 1086.C gp120-specific memory B cells at week 24 post-infection in HIV Env vaccinated and placebo recipient RMs (d). Each data point represents one animal, and medians are indicated as horizontal lines. Statistical analyses were performed using Wilcoxon signed-rank tests with exact p-values to compare Env vaccinated RMs’ plasma CH505 gp120 IgG binding and avidity responses, and Env vaccinated RMs’ CH505 gp120-specific memory B cells to 1086.C and b.63521-specific responses, followed by FDR adjustments for multiple comparisons. See Supplementary Table 5 for unadjusted p and FDR_p for all comparisons.