In a two-part seminar, Dan Littman discusses the opposing roles of Th17 cells. They protect mucosal surfaces from infection with bacteria and fungi, but they can also cause autoimmune inflammation. Littman also explains that different commensal microbes in our gut elicit different T cell responses, either pathogenic or non-pathogenic.

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Part One: Th17 cells and innate lymphoid cells in defense and disease

Part Two: Shaping of immune responses by the microbiota