THE ALPHA-BETA-T-CELL RECEPTOR CLUSTERING UPON SUPERANTIGEN MHC RECOGNITION/

Antigen recognition by T cells is the key event for the antigen specif ic immune responses to be triggered. This recognition is initiated by the binding of the T cell receptor (TCR) to antigen peptide/major hist ocompatibility complex (MHC) on the surface of the antigen presenting cells. TCR on most of the T cells is a heterodimer composed of alpha a nd beta chains which are associated with CD3 gamma delta epsilon as we ll as zeta chains, the signal transmission molecules. The dynamics of this TCR complex upon antigen/MHC recognition, however, has not been w ell understood. In this paper the authors analyse the configuration of TCR complex on T cells from a TCR beta chain gene transgenic mouse (T GM) strain. Unlike many other TGM strains reported, a considerable pro portion of T cells from this TGM expresses both transgene-encoded (V b eta 3) and endogenous TCR beta chains on their surface. By immunopreci pitation and immunoblotting analysis of T cells stimulated with a supe rantigen, 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.