Specific cooperative induction by KLH or invertebrate hemolymphs of mouse polyclonal T-cell-mediated cytolysis

Abstract

We previously showed that cells from mice primed in vivo with xenogeneic vertebrate serum can generate cytolytic T cells in vitro after boosting with the same serum. We investigated whether this would occur using any antigenic stimulus. We found in fact that (1) a number of conventional antigens were relatively inefficient at inducing cytolysis, (2) in contrast, KLH (a partially purified preparation of keyhole limpet hemocyanin) was efficient at inducing cytolysis, (3) induction in this case was KLH specific while cytolysis once induced had a polyclonal specificity for syngeneic and allogeneic tumor target cells, (4) mixtures of irradiated KLH-primed cells and normal spleen cells led to the generation of cytolytic cells, which was consistent with the existence of a first population of KLH-specific “promoter” cells triggering a second population of cells to polyclonally differentiate into cytolytic cells, and (5) not only vertebrate xenosera and KLH (a component of an invertebrate hemolymph) but also invertebrate hemolymphs themselves could specifically induce T-cell-mediated cytolysis. The question is raised in the Discussion section as to the nature and possible homology of those components present in both vertebrate sera and invertebrate hemolymphs, which are especially efficient at stimulating promoter cells. Also, from these and other results it is clear to us that indirectly KLH may do much more to the T-cell immune system than just stimulate KLH-specific cells.