The immunodepressive effect of Friend virus III. Effects on spleen T cells.

We have examined various T lymphocyte functions in the spleens of mice infected 4 days previously with Friend viurs (FV) in order to analyse its effect on the antibody response. We have found (a) that infection does not reduce the percentage of T lymphocytes in the spleen, nor their ability to respond to PHA, (b) that infected spleen cells mediate allogeneic augmentation of the primary response to SRBC in vitro, even though their own depressed response cannot be restored via the allogeneic effect, and (c) that infected spleen cells restore responses to SRBC by both allogeneic and syngeneic spleen cell cultures depleted of T lymphocytes. These results suggest that FV does not affect spleen T lymphocyte proliferation of helper function. Since macrophages from infected spleens cooperate normally in the response to SRBC in vitro, we conclude that the immune defect resides in the B lymphocytes.