Abundance of H‐2 promiscuous T cells specific for mycobacterial determinants in H‐2b/dF1 hybrid mice

摘要

AbstractA majority of immunodominant epitopes of mycobacterial antigens are known to be recognized by murine T cells in the context of several H‐2 haplotypes. In this study, we established the frequency of T cells able to recognize these peptides promiscuously,i.e.in the context of allogeneic antigen‐presenting cells, using hybridomas from peptide‐immunized H‐2 homologous and heterologous mice. The degree of promiscuity in homozygous mice varied between 4–27 between different specificities and genetic backgrounds. In particular, the results showed that promiscuity between Aband Adin respect to a peptide from theMycobacterium tuberculosis38‐kDa protein (residues 350–369) was displayed by 22 of BALB/c and 4 of C57BL/10‐derived hybrids, but by 42 of BALB/c x C57BL/10 F1‐derived clones. This represents a significant increase (p<0.001) of T cell promiscuity compared to the parental haplotypes. It is noteworthy that considerably lower peptide concentrations were able to stimulate the promiscuous hybridomas compared to the H‐2‐restricted hybrids. This finding suggests a functional advantage of promiscuous T cells which enables them to expand preferentially in the initial stages of infections withM. tuberculosisand thus enables the host to mount a rapid prote