Influence of pre-existing antibody responses. (A) (Top) Correlation analysis of baseline titers versus maximum titer increases of antibodies directed to gp120 (left) and p24 (right); n = 46. (Bottom) The absolute amount of antigen to induce a 2-fold increase in titers against gp120 (left) and p24 (right) was estimated by calculating the total viremia load (AUC). Antigen levels were correlated with baseline activities against these antigens (n = 22, group A; Table 1). (B) Correlation analysis of baseline anti-gp120 titers versus maximum anti-p24 titer increases and slope of anti-p24 response (n = 46). For both panels, all significant observations were significant on the individual level and also after Bonferroni correction.