Proliferative reactivity of T cells to autologous, cell-associated antigens.

T cells capable of proliferating in response to signals from autologous cells can be demonstrated in normal peripheral blood. The stimulating cell is contained among populations enriched in B cells, "null" cells, and monocytes, but not among populations enriched in T cells. Density gradient fractionation indicated that the autologous reactive T cell may represent a subpopulation of cells responsive in allogeneic mixed lymphocyte cultures. This was confirmed by negative selection (BUDR and light) experiments which also indicated that the "autologous" stimulus can be mediated by at least some allogeneic cells. In a portion of patients with active systemic lupus erythematosus, autologous reactivity was reversibly blocked. Prior incubation of either responding T or stimulator cells at 37 degrees C restored this reactivity.