The alpha beta T cell receptor clustering upon superantigen/MHC recognition.

Abstract

Antigen recognition by T cells is the key event for the antigen specific immune responses to be triggered. This recognition is initiated by the binding of the T cell receptor (TCR) to antigen peptide/major histocompatibility complex (MHC) on the surface of the antigen presenting cells. TCR on most of the T cells is a heterodimer composed of alpha and beta chains which are associated with CD3 gamma delta epsilon as well as zeta chains, the signal transmission molecules. The dynamics of this TCR complex upon antigen/MHC recognition, however, has not been well understood. In this paper the authors analyse the configuration of TCR complex on T cells from a TCR beta chain gene transgenic mouse (TGM) strain. Unlike many other TGM strains reported, a considerable proportion of T cells from this TGM expresses both transgene-encoded (V beta 3) and endogenous TCR beta chains on their surface. By immunoprecipitation and immunoblotting analysis of T cells stimulated with a superantigen, staphylococcal enterotoxin B (SEB), the authors found that V beta 3 was coprecipitated with V beta 8, demonstrating the clustering of TCR alpha beta upon superantigen/MHC recognition.