In vivo generation of hapten-specific killer T cells without elimination of suppressor cells.

We have provided evidence to demonstrate that hapten-specific killer cells can be generated in vivo toward hapten-conjugated syngeneic splenic cells. The critical aspect is to provide an auxillary cellular antigenic stimulus in addition to the hapten-conjugated syngeneic cells. In our experiments this stimulus was CBA/J splenic cells that possess MIs disparate but H-2 compatible antigens with C3H/HeN hosts. The Mls antigen has been shown by others to activate helper T cells in vitro to synthesize KAF, a signal that prekiller cells require besides target antigen. Killer cells (shown to be T cells) as well as helper T cells were found to be derived from the C3H host. Induction in the host animal of partial tolerance to the auxiliary cells possessing Mls antigen abrogated the response. This system, besides providing a better understanding of the control mechanisms involved in the development of T killer cells in vivo, points to a way in which the latter may be generated-ng suppressor cells. The latter principle may prove highly useful in certain clinical situations.