Staphylococcal enterotoxin B: immunolabeling and visualization of target cells

Binding of staphylococcal enterotoxin B (SEB) to cultured cells and to tissue sections containing presumed target sites was detected by use of an immunofluorescence sandwich technique. A triple sandwich with successive incubations of SEB, rabbit anti-SEB, and fluorescein-conjugated goat anti-rabbit secondary antibody was applied to samples. Binding of SEB to rat basophilic leukemia (RBL) cells, mast cells of rat dorsal skin, and cells of leukocyte-enriched human plasma was observed. Our results point out and reinforce the reported involvement of SEB in various biological effects that appear to implicate leukocytes, either as mast cells residing in tissues or as white cells circulating in the bloodstream.