Human TCR-MHC coevolution after divergence from mice includes increased nontemplate-encoded CDR3 diversity.

ABSTRACT: For thymic selection and responses to pathogens, T cells interact through their αβ T cell receptor (TCR) with peptide-major histocompatibility complex (MHC) molecules on antigen-presenting cells. How the diverse TCRs interact with a multitude of MHC molecules is unresolved. It is also unclear how humans generate larger TCR repertoires than mice do. We compared the TCR repertoire of CD4 T cells selected from a single mouse or human MHC class II (MHC II) in mice containing the human TCR gene loci. Human MHC II yielded greater thymic output and a more diverse TCR repertoire. The complementarity determining region 3 (CDR3) length adjusted for different inherent V-segment affinities to MHC II. Humans evolved with greater nontemplate-encoded CDR3 diversity than did mice. Our data, which demonstr

SUBMITTER: Chen X 

PROVIDER: S-EPMC5679170 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature