Fig. 5: Memory B-cell responses following Delta challenge and RBD-62 treatment.

NHP were challenged with 2 × 10⁵ TCID₅₀ Delta and simultaneously treated with RBD-62 or PBS. Memory B-cell specificity was determined at day 14 post challenge via binding to fluorochrome-labeled variant probe pairs as indicated in figure legends. Probe pairs include WA1 and Delta S-2P, Delta and BA.1 S-2P, and Delta S-2P and RBD-62. a Representative flow cytometry graphs for one animal in the control group (left) or treated group (right). Event frequencies denote the proportion of probe-binding cells within the total class-switched memory B-cell population. Cross-reactive memory B cells are represented by events in the top right quadrant whereas single-positive memory B cells reside in the top left or bottom right quadrants. b Pie charts indicating the geometric mean frequency of the entire S-specific memory B-cell compartment capable of binding to both members of a variant probe pair (dark gray) or a single variant within the pair (light gray or black) at day 14 post challenge. The control group is displayed on the left and the treated group is displayed on the right. n = 8 for treated group and n = 4 for control group. Source data are provided as a Source Data file.