Purified KSHV antigens stimulate T-cell proliferation. Responses to KSHV whole viral particles (A-B) and KSHV lysate (C-D). Each patient tested is shown by a different mark at each stimulator-responder ratio (the points for each patient are not connected for clarity). Isotype antibody had no effect on results; anti-CD91 reduced responses. Results of δ-cpm (A,C) and the stimulation index (B,D) are shown.