Effect of allogeneic feeder cells from HIV-seronegative and HIV-seropositive patients on the development of Tc2 clones. Purified CD8⁺ T cells from one HIV-seronegative patient were directly cloned in limiting numbers in the presence of irradiated allogeneic feeder cells from two HIV-seronegative (□) and four HIV-seropositive patients (▪) plus PHA and IL-2. Clonal supernatants, obtained as described in the legend to Fig 1, were assayed for cytokine content, as described in Materials and Methods. The percentages of cytokine-producing clones generated in the presence of different allogeneic feeder cells (upper panel), and the mean values (±SE) of the cytokine produced by the two group of clones (clones derived in the presence of feeder cells from HIV-seropositive and HIV-seronegative patients) (lower panel) are reported.