Induction of interleukin-8 in human neutrophils after MHC class II cross-linking with superantigens

Neutrophils have been shown to express major histocompatibility complex cla ss II (MHC II) after stimulation. However, reports concerning the functiona l effect of MCH II expression are still lacking. In our hands, granulocyte- monocyte colony-stimulating factor (GM-CSF) alone and in combination with i nterferon (IFN)-gamma, but not IFN-gamma or interleukin (IL)-3, induced a s ignificant level of expression of human leukocyte antigen DR on neutrophils , The addition of staphylococcal enterotoxin E to neutrophils resulted in a significant increase in IL-8 production only after prestimulation with GM- CSF alone or in combination with IFN-gamma but had no effect on neutrophils preincubated with IFN-gamma alone or IL-3, Staphylococcal enterotoxin A, a nother bivalent superantigen, also stimulated production of IL-8 by preincu bated polymorphonuclear neutrophils, whereas staphylococcal enterotoxin A m utants that are not able to cross-link MHC II molecules failed to induce IL -8 production. Taken together, our results clearly demonstrate that after i nduction of MHC II, neutrophils are able to respond to MHC II-specific stim ulation. These findings support the ideas that the induced MHC II complex i s completely functional and that neutrophils may be able to present antigen s.