DELINEATION BY USE OF SPECIFIC MONOCLONAL-ANTIBODIES OF THE T-CELL RECEPTOR AND MAJOR HISTOCOMPATABILITY COMPLEX INTERACTION SITES ON THE SUPERANTIGEN TOXIC SHOCK SYNDROME TOXIN-1

Murine monoclonal antibodies (MAbs) specific for toxic shock syndrome toxin 1 (TSST-1), a bacterial superantigen, showed the ability either to detect TSST-1 bound to histocompatibility locus antigen (HLA)-DR mo lecules or to inhibit TSST-1 binding to HLA-DR. A MAb capable of detec ting DR-bound TSST-1 could also inhibit the toxin-induced activation o f a T-cell receptor V beta 15-expressing murine T-cell hybridoma. Alte rnatively, MAbs with specificity for the HLA-DR association site could present TSST-1 in vitro, stimulating CD4(+) human T cells to prolifer ate. These functional activities correlated directly with MAb specific ity for HLA-DR versus T-cell receptor V beta interaction sites on TSST -1 as determined by reactivity with a panel of recombinant TSST-1 muta nt molecules. Therefore, these MAbs discriminate the superantigen func tional sites on the TSST-1 molecule and constitute reagents with the p roperty of being potent modulators of the toxic activity of TSST-1.