Assessment of serum binding and autologous neutralization titers in RM.

(A) The immunization schedule for the UM1 vaccine efficacy study is plotted along a timeline in weeks, with key time points indicated. The vaccination arms of the trial are shown on the left and the agents used for immunization are indicated at the top. SOSIP indicates BG505 SOSIP.664.N332. The adjuvant used was 3M-052. HVV = heterologous viral vectors, each expressing SIVmac239 Gag (no Env); VSV-Gag = vesicular stomatitis virus; VV-Gag = vaccinia virus; Ad5-Gag = adenovirus type 5. Ten low dose repeated intra-vaginal challenges using SHIV.BG505 were carried out weekly beginning at week 84. BG505 SOSIP-specific serum IgG measured by ELISA on the day of challenge (week 84) and is shown for (B) vaccine groups (p>0.05) and (C) protected vs. infected RM (p>0.05). There was no significant difference between vaccine or challenge outcome groups using the Mann-Whitney test. (D) Neutralization activity against BG505 Env PV is shown for the vaccination groups, and was not significantly different using a Mann-Whitney test (p>0.05). A significant correlation was observed between serum nAb titers measured at week 84 against BG505 Env PV T332N and the T332 version (Spearman’s Rank, r = 0.7932, p<0.0001). ID₅₀ titers were calculated using GraphPad Prism. For (B) through (D), the horizontal bar represents the median for each group.

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