Find in Library

Mucosal-Associated Invariant T (MAIT) cells have been shown to play protective roles during infection with diverse pathogens through their propensity for rapid innate-like cytokine production and cytotoxicity. Among the potential applications for MAIT cells is to defend against <i>Staphylococcus aureus</i>, a pathogen of serious clinical significance. However, it is unknown how MAIT cell responses to <i>S. aureus</i> are elicited, nor has it been investigated whether MAIT cell cytotoxicity is mobilized against intracellular <i>S. aureus</i>. In this study, we investigate the capacity of human MAIT cells to respond directly to <i>S. aureus</i>. MAIT cells co-cultured with dendritic cells (DCs) infected with <i>S. aureus</i> rapidly upregulate CD69, express IFNγ and Granzyme B and degranulate. DC secretion of IL-12, but not IL-18, was implicated in this immune response, while TCR binding of MR1 is required to commence cytokine production. MAIT cell cytotoxicity resulted in apoptosis of <i>S. aureus</i>-infected cells, and reduced intracellular persistence of <i>S. aureus</i>. These findings implicate these unconventional T cells in important, rapid anti-<i>S. aureus</i> responses that may be of great relevance to the ongoing development of novel anti-<i>S. aureus</i> treatments.