THE J-BETA SEGMENT OF THE T-CELL RECEPTOR CONTRIBUTES TO THE V-BETA-SPECIFIC T-CELL EXPANSION CAUSED BY STAPHYLOCOCCAL-ENTEROTOXIN-B AND URTICA-DIOICA SUPERANTIGENS

We have used a new polymerase chain reaction-based technique to analyz e at the clonal level the CDR3 diversity and the JP usage associated w ith the V beta-dependent cell receptor (TCR) recognition of two supera ntigens: the staphylococcal enterotoxin B and the Urtica dioica agglut inin. Our results show that a subset of J beta elements is preferentia lly expanded in a given V beta family, independently of the nature of the superantigen. By contrast, the CDR3 loop does not contribute signi ficantly to the T cell expansion induced by the superantigens. We conc lude that the J beta segment of the TCR beta chain, but not the CDR3 r egion, participates in superantigen binding, presumably by influencing the quaternary structure of the TCR beta chain.