Class II MHC-expressing myofibroblasts play a role in the immunopathogenesis associated with staphylococcal enterotoxins.

Food poisoning due to staphylococcal enterotoxins (SEs) affects hundreds of thousands of people each year. Little is known about how SEs initiate immune responses and cause pathogenesis. Here, we demonstrate that cultured human intestinal myofibroblasts (IMFs) bind SEs in an MHC class II-dependent fashion. IMFs respond to SE exposure with increased secretion of IL-6, IL-8, and TNF-alpha. A significant proliferative T cell response was observed when MHC class II-expressing IMFs were pulsed with SEA and cocultured with human CD4(+) T cells. In conclusion, our findings support the hypothesis that IMFs may play an important role in pathology associated with staphlococcocal enterotoxigenic disease.