STAPHYLOCOCCAL ENTEROTOXINS BIND H-2D(B) MOLECULES ON MACROPHAGES

We screened a panel of monoclonal antibodies against selected macropha ge cell surface molecules for their ability to inhibit enterotoxin bin ding to major histocompatibility complex class II-negative C2D (H-2(b) ) macrophages, Two monoclonal antibodies, HB36 and TIB126, that are sp ecific for the alpha 2 domain of major histocompatibility complex clas s I, blocked staphylococcal enterotoxins A and B (SEA and SEE, respect ively) binding to C2D macrophages in a specific and concentration-depe ndent manner. Inhibitory activities were haplotype-specific in that SE A and SEE binding to 11-2(k) or H-2(d) macrophages was not inhibited b y either monoclonal antibody, HB36, but not TIE126, inhibited enteroto xin-induced secretion of cytokines by H-2(b) macrophages, Lastly, pass ive protection of D-galactosamine-sensitized C2D mice by injection wit h HB36 antibody prevented SEE-induced death, Therefore, SEA and SEE bi nding to the alpha 2 domain of the H-2D(b) molecule induces biological activity and has physiological consequences.