Figure 4.

Immune responses following SARS-CoV-2 challenge. Rhesus macaques were vaccinated and challenged as described in Figure 2 . SARS-CoV-2 neutralizing antibodies (A) were measured at the time of challenge (week 20) and 2 weeks post-challenge (week 22) by PRNT, and RBD-specific IFN-γ T-cell responses (B) were measured 2 weeks post-challenge by ELISpot. (A) Symbols represent individual PRNT50 titers; horizontal bars depict the GMT of the group. For comparison, PRNT50 titers and GMT of 10 human plasma samples positive for SARS-CoV-2 antibodies (human convalescents) are shown. (B) Symbols represent individual spot-forming units (SFU) per one million PBMCs; horizontal bars depict mean SFU per one million PBMCs. Different symbol shapes represent individual animals, and the same symbol shapes are used for the same animals throughout all post-challenge data.