T cell derived cytokines are critical for mediating host defense against infectious disease, but they also mediate disease pathology in autoimmunity. A subset of CD4+ T cells, known as "Th17 cells" based on production of the cytokine IL-17, plays a key role in driving autoimmunity. Conversely, IL-17 and Th17 cells play important roles in fungal immunity, particularly in protection against opportunistic mucosal infections caused by the commensal yeast Candida albicans,first shown by Dr. Gaffen's group. IL-17 and its receptor are unique in structure and sequence from other known cytokines, and the Gaffen lab has been a leader in studying signaling pathways mediated by this this novel family of cytokines. In addition, antibodies against IL-17 and its receptor were recently approved by the FDA to treat autoimmune conditions, particularly psoriasis

The Gaffen lab studies three aspects of IL-17/Th17 cell biology: (1) mechanisms of molecular signal transduction mediated by IL-17 and its receptor (2) means by which IL-17 mediates host defense against mucosal Candida albicans fungal infections, and (3) mechanisms by which dysregulated IL-17/Th17 cells drive pathogenesis of autoimmunity.