Figure 4.

Three doses of noNAG-RBD-E2p elicits a potent and focused neutralizing antibody response in NHPs

(A) Immunization schedule for rhesus macaques.

(B) Spike-binding serum antibody titers. Each point represents an individual animal measured in triplicate. Bars indicate median values and 95% confidence intervals.

(C) Spike-/ACE2-blocking antibody titers using recombinant spike protein from WA1, Beta, or Delta variants, depicted as described in (B). Horizontal dashed line indicates limit of detection. Statistical comparisons were made using a Kruskal-Wallis ANOVA followed by Dunn’s comparison with FL-S-2P, corrected for multiple comparisons. n = 8 animals for dose 2 groups, and n = 4 animals for dose 3 groups. “ns” indicates a p value > 0.05.

(D) FRNA neutralizing antibody titers against authentic WA-1 and Omicron BA.5 variants. Depicted as described for (B). Each point represents an individual animal measured in quadruplicate. The 4- and 40-μg noNAG-RBD-E2p groups are combined for analysis, with the 4-μg group depicted in light red and the 40-μg group depicted in dark red. Statistical comparisons were made using a two-tailed Mann-Whitney U test; n = 8 animals per group.

(E) PRNT neutralizing antibody titers against WA-1. Depicted as described in (D). Each point represents an individual animal measured in duplicate.

(F) Antibody quality calculated by normalizing neutralizing titers to spike-binding titers, depicted as described in (D).

See also Figures S5 and S6 and Table S1.