Associations between initial neutralizing antibody potency and rate of declining neutralization potency over time.

For each neutralizing antibody (NAb), the geometric mean (GM) IC₅₀ was determined for all PSVs from an earlier and later decade period, as shown in the x-axis title. Fold change in NAb potency was determined between the earlier and later decade periods. A positive fold change in Env sensitivity to a given NAb indicates increasing sensitivity (earlier PSV GM IC₅₀ > later PSV GM IC₅₀), while a negative fold indicates decreasing sensitivity over time (earlier PSV GM IC₅₀ < later PSV GM IC₅₀). The vertical dashed line at 1 indicates no observed change. The correlation between the fold change in NAb potency over time and the potency of the NAb against PSVs from the earlier decade period are shown for (A) subtype B from the United States, (B) CRF01_AE from Thailand, (C) subtype A2 from East Africa, (D) subtype D from Uganda, and (E) subtype C from South Africa. Individual NAbs are shown as unique symbols colored by target specificity, including NAbs targeting the V1V2 (orange), V3 (blue), CD4bs (green) and MPER (purple) domains. Correlations were evaluated by Spearman correlation analysis. The summary of fold change in NAb potency over a ten-year period is shown for (F) all NAbs from all regions; data are stratified by initial NAb potency and significant differences were determined by Mann Whitney U test; ** = p<0.001, *** = p<0.0001.