(A) HIV-1 infection kinetics for rectal explants from VRC01-infused participants challenged with VRC01 neutralization–sensitive HIV-1Bal26. Graphs are arranged by infusion dose (left, 10 mg/kg; right, 30 mg/kg) and collection time postinfusion (n = 7). Each curve corresponds to the infection readout of a single tissue explant section challenged with virus. Dashed black lines represent the threshold for detecting infection, defined by the average log RLU plus 2 standard deviations of explants challenged with Bal26 in the presence of bn-mAbs or antiretrovirals (n = 32). (B) Total HIV-1Bal26 replication for individual explants from VRC01-infused (color-coded squares, n = 7) or uninfused control (black/gray symbols, n = 5) participants, summarized by scaled log RLU AUC. Control explants were challenged in the absence or presence of VRC01 added ex vivo, at the indicated concentrations, demonstrating the relative sensitivity of this virus to VRC01 in an explant culture assay. Unique symbols are used to denote explants from different donors. Statistical significance was assessed by Dunn’s tests.