EBV, but not wild-type rhLCV, is sensitive to 72A1 neutralization. (A) CFSE-labeled human PBMC were exposed to medium, EBV, or EBV pretreated with 100, 50, or 25 ng/ml recombinant 72A1. Proliferation was detected using flow cytometry by gating live CD20+ cells and monitoring the reduction in CFSE intensity. The percentages of proliferating (CFSE-low) B cells are indicated. (B) CFSE-labeled rhesus macaque PBMC were similarly assayed following exposure to medium, rhLCV, or rhLCV pretreated with 100, 50, or 25 ng/ml recombinant 72A1.