FIG. 4.

Effect of DST and anti-CD154 MAb on LCMV-induced CTL activity. C57BL/6 mice were pretreated with a single donor-specific BALB/c spleen cell transfusion and a brief course of anti-CD154 MAb and then given a BALB/c skin graft as described in Materials and Methods. Groups of mice bearing intact grafts were infected with LCMV on day 1, 15, 50, or 70 after skin transplantation. T cells from these mice were tested in 7- to 8-h chromium-51-release assays for cytotoxicity against LCMV-infected syngeneic MC57G cells (A, D, G, and J), uninfected MC57G cells (B, E, H, and K), or allogeneic P-815 cells (C, F, I, and L). Open symbols represent the percent lysis mediated by splenocytes from mice treated with DST and anti-CD154 MAb and skin grafted. Solid symbols represent cytotoxicity mediated by control thymectomized mice infected with LCMV. In the day 70 experiment, the ×-× symbols refer to lysis by cells from LCMV-infected normal nonthymectomized mice that were used as the controls.