An endogenous positively selecting peptide enhances mature T cell responses and becomes an autoantigen in the absence of microRNA miR-181a.

ABSTRACT: Thymic positive selection is based on the interactions of T cell antigen receptors (TCRs) with self peptide-major histocompatibility complex (MHC) ligands, but the identity of selecting peptides for MHC class II-restricted TCRs and the functional consequences of this peptide specificity are not clear. Here we identify several endogenous self peptides that positively selected the MHC class II-restricted 5C.C7 TCR. The most potent of these also enhanced mature T cell activation, which supports the hypothesis that one function of positive selection is to produce T cells that can use particular self peptide-MHC complexes for activation and/or homeostasis. We also show that inhibiting the microRNA miR-181a resulted in maturation of T cells that overtly reacted toward these erstwhile positively

SUBMITTER: Ebert PJ 

PROVIDER: S-EPMC3762483 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature