Cell interaction in B/W mice: a reversible defect at the T-cell level.

The anti-SRBC PFC response of old B/W mice can be restored by adding specifically activated T cells or primed spleen cells in vitro as well as by injecting LPS and SRBC in vivo. Since nonresponsive old B/W bone marrow and thymocytes cooperated in a normal manner upon adoptive transfer, this suggested that the lack of response to SRBC in the intact animal was due to a block in T cell activation and not due to intrinsic defects in lymphoid cells necessary to initiate a response. The block in T cell activation might be mediated by a suppressor cell found in old B/W spleens and it was hypothesized that this suppressor might also lead to a loss of self-tolerance.