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

We screened a panel of monoclonal antibodies against selected macrophage cell surface molecules for their ability to inhibit enterotoxin binding to major histocompatibility complex class II-negative C2D (H-2(b)) macrophages, Two monoclonal antibodies, HB36 and TIB126, that are specific for the alpha 2 domain of major histocompatibility complex class I, blocked staphylococcal enterotoxins A and B (SEA and SEE, respectively) binding to C2D macrophages in a specific and concentration-dependent manner. Inhibitory activities were haplotype-specific in that SEA and SEE binding to 11-2(k) or H-2(d) macrophages was not inhibited by either monoclonal antibody, HB36, but not TIE126, inhibited enterotoxin-induced secretion of cytokines by H-2(b) macrophages, Lastly, passive protection of D-galactosamine-sensitized C2D mice by injection with HB36 antibody prevented SEE-induced death, Therefore, SEA and SEE binding to the alpha 2 domain of the H-2D(b) molecule induces biological activity and has physiological consequences.