T-lymphocyte specificity differences to horse cytochrome c in different lymphoid cell compartments.

T-lymphocyte proliferative responses were determined with peripheral blood lymphocytes (PBL), peritoneal exudate lymphocytes (PEL) and lymph node lymphocytes (LNL) of guinea pigs immunized with horse cytochrome c (HCytc). The proliferative response of PBL activated by peptide 81-104 from animals immunized with HCytc was equal to or better than HCytc while the proliferative response activated by peptide 1-65 was small and no reactivity was seen when peptide 66-80 was tested. In contrast, the proliferative responses of PEL and LNL stimulated by peptide 1-65 approached those activated by HCytc, while peptide 81-104 was far less effective. The differences in the proliferative responses of PBL and PEL activated by peptide 81-104 and peptide 1-65 suggest that different lymphoid compartments may have T-cells directed to different T-cell epitopes displayed on the same antigen. The possible roles of different T-cell clones, antigen processing, and differential induction of suppressor cells are discussed in relation to these findings.