Nonresponsiveness of AKR.H-2b congenic mice for anti-AKR/Gross MuLV CTL responses: involvement of inhibitory cells as defined by adoptive transfer experiments.

AKR.H-2b mice are unable to elicit AKR/Gross murine leukemia virus (MuLV)-specific cytolytic T lymphocyte (CTL) responses. The participation of inhibitory cells was addressed through adoptive transfer experiments utilizing young AKR.H-2b:Fv-1b congenic responder mice as the recipients of AKR.H-2b donor cells. The adoptive transfer of unfractionated viable splenocytes led to inhibition of virus-specific CTL responsiveness without affecting minor histocompatibility or allogeneic (H-2d)-specific CTL responses. Negative cell selection studies indicated that of the donor AKR.H-2b spleen cells that mediate specific inhibition, B lymphocytes, CD4-CD8+ and CD4+CD8- T lymphocytes, but not macrophages, even though they are viral antigen positive (as are B and T lymphocytes), were the cells responsible for the diminution of the generation of AKR/Gross virus-specific CTL by AKR.H-2b:Fv-1b mice. To evoke maximal inhibition, the adoptive transfer of AKR.H-2b cells had to be performed prior to in vivo priming with viral antigen. Anti-AKR/Gross MuLV nonresponsiveness of AKR.H-2b mice could not be overcome through utilization of exogenous IL-2 at either the priming or in vitro restimulation phases of CTL generation. These results illustrate the complex interaction between retroviruses and lymphocytes and are relevant to understanding how retrovirus-infected cells may not only escape immune surveillance themselves, but also may inhibit the cytolytic T cell response directed at other infected cells, such as tumor cells.