Specific suppression elicited by EL4 lymphoma cells in syngeneic mice. Specificity includes self-antigens on EL4.

In vivo, subclones derived from EL4 lymphoma cells generate suppressor T lymphocytes specific for anti-EL4 immune responses. Spleen cells of EL4-sensitized C57BL/6 mice down-regulate the in vitro induction of EL4-specific cytolytic T lymphocytes (CTL). In addition, EL4-sensitized spleen cells interfere with the antigen response of two T lymphocyte clones. These recognize, in an H-2b context, a self-antigen on spleen cells that is also expressed by transformed cells, including EL4. The simultaneous anti-self and anti-EL4 specificity of the helper and suppressor activities suggests, therefore, that they are the product of an in vivo autoimmune reaction to EL4. The anti-self suppression might aim to re-establish self-tolerance, at the same time down-regulating responses against immunogenic epitopes that are co-expressed with the self-antigen on the EL4 cells. This agrees well with our observation that suppressor T cells, apparently elicited by suppressogenic epitopes on non-immunogenic EL4 subclones, down-regulate the CTL response elicited by immunogenic EL4 subclones. The additional self-specificity of this suppression indicates that the suppressogenic epitopes at least in part represent EL4 self-antigens.