Helper cell-independent cytolytic T lymphocytes specific for a minor histocompatibility antigen.

We have isolated several anti-H-2Db-restricted cytolytic T cell clones specific for the minor histocompatibility antigen, H-1, from a long-term B10.129(5M) anti-C57BL/6 mixed leukocyte culture. All proliferate significantly, in the absence of exogenously added lymphokine, and in a specific manner to H-2Db-compatible stimulator cells that carry the appropriate H-1 minor antigen. Moreover, significant proliferation also occurs when T cell-depleted stimulator cells are used as the antigenic stimulus, indicating that the proliferative capacity of these clones is not the result of T cell factors produced by the stimulator cells. After concanavalin A stimulation, IL 2-like lymphokine activity can be detected from the one clone tested, 5M/B6-5. These data demonstrate the existence of antigen-driven, helper T cell-independent cytolytic T cell clones responsive to a single minor histocompatibility antigen. The implications of this finding are discussed.