Generation of cytotoxic lymphocytes in the autologous mixed lymphocyte culture.

We have studied the ability of purified B lymphocytes to generate cytotoxic T lymphocytes in autologous mixed leukocyte cultures (MLC). Cytotoxic lymphocytes were produced but only autologous mononuclear cells stimulated by lipopolysaccharide (LPS) were susceptible target cells. Unstimulated mononuclear cells and purified B cells were not susceptible to killing by cytotoxic cells generated in the autologous MLC. This suggests that the target antigen may be expressed on stimulated or dividing B lymphocytes in a way that renders the cells more susceptible to cytolysis. Autologously stimulated cytotoxic effector cells were found to exhibit specificity. Cy totoxicity for autologous LPS-stimulated target cells occurred but not for an allogeneic, B cell, histiocytic lymphoma cell line. It is postulated that cytotoxic T cells generated in the autologous MLC may play a role in immune surveillance or in regulation of the immune system.