PRESENCE OF HOST-REACTIVE T-CELLS IN LYMPHOHEMATOPOIETIC CHIMERAS

Abstract

The presence of autoreactive lymphocytes was investigated in murine lymphohematopoietic chimeras. The presence of precursors of host-reactive cytotoxic effector T lymphocytes in parent .fwdarw. F1 chimeras is demonstrated. Lymphocytes from these chimeras display cytotoxic activity towards the nonshared major histocompatibility complex (MHC) antigens of the host following activation with the polyclonal T-cell activator concanavalin A. These host-reactive cells were found despite the apparent absence of lymphocytes demonstrating autoreactivity in other experimental systems: mixed lymphocyte reaction, cell-mediated lympholysis, positive allogeneic effect and negative allogeneic effect. Animals possessing precursors of cytotoxic effector cells also possess precursors of cytotoxic effector cells capable of generating an MHC-restricted anti-minor histocompatibility antigen response. The results are discussed in reference to the role of the thymus in effecting self/non-self discrimination.