FIG. 1.

CD8 T cells are essential for the control of CMV infection after BMT. Shown are Kaplan-Meier survival plots for groups of 20 mice, giving the survival rates (ordinate) as a function of time (abscissa) after syngeneic BMT, performed with the indicated doses of BMC, followed by intraplantar infection with murine CMV. Note that in the absence of infection, survival rates after hematoablative γ-ray treatment with 6 Gy ranged from 40 to 60% in groups without BMT and were 100% after reconstitution with any of the indicated doses of BMC (not shown). The dashed line indicates the control group given hematoablative γ-ray treatment with 6 Gy followed by infection but no BMT. In all other experimental groups, the recipients received BMC and were infected. The presence and absence of CD8 T cells are indicated by solid and open symbols, respectively. Solid squares indicate groups of recipients reconstituted by BMT with the indicated doses of BMC. Solid circles indicate immunotherapy by adoptive transfer of 10⁶ CD8 T cells. Open circles indicate adoptive transfer of 10⁶ CD4 T cells. Solid diamonds indicate in vivo depletion of CD4 T cells. Open diamonds indicate in vivo depletion of CD8 T cells.