The action of enterotoxins leads to increased chloride ion permeability of the apical membrane of intestinal mucosal cells.
[4] 25 staphylococcal enterotoxins (SEs), mainly produced by Staphylococcus aureus, have been identified to date and named alphabetically (SEA – SEZ).
A more distant relative of the family is the S. aureus toxic shock syndrome toxin, which shares only a low level of sequence similarity with this group.
Each superantigen possesses slightly different binding mode(s) when it interacts with MHC class II molecules or the T-cell receptor.
[14] A putative mode of toxicity is that NSP4 activates a signal transduction pathway that ultimately results in an increased cellular concentration of calcium and subsequent chloride secretion from the cell.
[15] Secretion of ions from villi lining the gut alter normal osmotic pressures and prevent uptake of water, eventually causing diarrhea.