Glycosphingolipids: the putative receptor for Staphylococcus aureus enterotoxin-B in human kidney proximal tubular cells.

We have investigated the binding of 125I-staphylococcal enterotoxin-B (SEB) in cultured human proximal tubular cells. We found that the binding of 125I-SEB to PT cells was time and concentration dependent and competitively inhibited by antibody against SEB. Preincubation of cells with trypsin and neuraminidase or with fetuin did not significantly impair the binding of 125I-SEB to such cells. In contrast, treatment with endoglycoceramidase completely inhibited the binding of 125I-SEB to cells. Neutral glycosphingolipids exerted a concentration-dependent inhibition of 125I-SEB binding to such cells, maximum inhibition (96% compared to control) occurred upon incubation of PT cells with neutral glycosphingolipids. Taken together, our studies indicate that SEB specifically binds to a neutral glycosphingolipid in PT cells. In contrast, staphylococcal enterotoxin-A and toxic shock toxin (TST-1) are bound to a protein in such cells.