Major histocompatibility complex-controlled, antigen-presenting cell-expressed specificity of T cell antigen recognition. Identification of a site of interaction and its relationship to Ir genes.

Abstract

Previously, studies were reported on a T lymphocyte hybridoma clone and the peritoneal exudate T cells (PETLES) from B10.A(5R) mice primed with the cytochrome c carboxyl terminal peptide (residues 81-103) of the tobacco horn worm moth (Manduca sexta). B10.A(5R) lymphocytes, low responders to pigeon fragment 81-104, were unable to respond to pigeon cytochrome 4c 81-104 fragment presented on syngeneic B10.A(5R) antigen-presenting cells (APC). These same T lymphocytes did respond to the pigeon fragment when presented on B10.A APC. Thus, some structural difference between the pigeon and moth peptides had prevented B10.A(5R) APC from effectively presenting the pigeon fragment to moth-primed B10.A(5R) lymphocytes. This structural difference was the deletion of Ala103 from the pigeon sequence in the moth peptide. Two additional T cell specificities were created by changing residue 99. These T cell populations from the B10.A(5R) showed an identical dependence on the Ala103 deletion when B10.A and B10.A(5R) APC were compared. The relationship of APC-expressed antigen specificity and MHC[major histocompatibility complex]-linked immune responsiveness differences was also examined. The B10.A(5R) was a high responder to each of 3 peptides that lack Ala103, but not to the Ala103-containing analogs. B10.A mice responded to both types of peptides. Using allogeneic antigen presentation to B10.A PETLES by pulsed APC, it was shown that the poor response of the B10.A(5R) to the Ala103-containing peptides was, in 2 of 3 cases, not associated with any differences in T cell repertoires, but due to 2 different APC capabilities of B10.A and B10.A(5R). The exception apparently represents a case of T cell repertoire polymorphism between b10.A and B10.A(5R) that can also affect immune responsiveness.