Analysis of the cross-reactive immune suppression induced by random copolymers of glutamic acid with tyrosine and alanine

Cross reactivity in the induction of immune suppression by the structurally related polymers of L glutamic acid, L alanine, and/or L tyrosine (GAT, GA, GT) was studied. SJL (H 2⁸) and DBA/1 (H 2q) mice are nonresponders to GAT and GT, whereas SJL, but not DBA/1 responds to GA. Both strains respond to these polymers when complexed to the immunogenic carrier methylated bovine serum albumin (MBSA). Preimmunization with GA suppresses GA MBSA as well as GAT MBSA and GT MBSA plaque forming cell (PFC) responses in DBA/1 mice. Likewise, GAT suppresses GAT MBSA and GA (SJL) and GA MBSA (DBA/1) PFC responses in both strains while being totally ineffective on GT MBSA responses. GT preimmunization suppressed GA, GAT MBSA, and GT MBSA PFC responses in SJL but not DBA/1 responses. This study demonstrates that cross reactive immune suppression does not follow predictable patterns based upon cross reactivity of specific antibodies and that cross suppression is not reciprocal.