A variable immunoreceptor in a subpopulation of human neutrophils

Neutrophils are thought to rely solely on nonspecific immune mechanisms. Here we provide molecular biological, immunological, ultrastructural, and functional evidence for the presence of a T cell receptor (TCR)-based variable immunoreceptor in a 5-8% subpopulation of human neutrophils. We demonstrate that these peripheral blood neutrophils express variable and individual-specific TCR alpha beta repertoires and the RAG1/RAG2 recombinase complex. The proinflammatory cytokine granulocyte colony-stimulating factor regulates expression of the neutrophil immunoreceptor and RAG1/RAG2 in vivo. Specific engagement of the neutrophil TCR complex protects from apoptosis and stimulates secretion of the neutrophil-activating chemokine IL-8. Our results, which also demonstrate the presence of the TCR in murine neutrophils, suggest the coexistence of a variable and an innate host defense system in mammalian neutrophils.