Secondary cytotoxic allograft responses in vitro. III. The immunogenicity of allogeneic membrane fragments.

The immunogenicity of murine membrane fragments was tested both in primary and in secondary in vitro cytotoxic allograft responses, and compared to that of intact allogeneic stimulator cells. Allogeneic membrane fragments induced poor proliferative and cytotoxic responses in normal splenic responder cells. However reexposure of immune responder T cells to allogeneic membrane fragments triggered the generation of highly reactive cytotoxic T lymphocytes (CTL). Moreover, the generation of secondary CTL as induced by allogeneic membrane fragments was preceded by only a marginal cell proliferation. The results obtained are compatible with the concept that serologically defined (SD) antigens alone are capable of triggering alloimmune T cells to differentiate highly reactive secondary CTL.