Protective Role of IL-17 in Pulmonary Tuberculosis Relapse

Abstract Tuberculosis (TB) recurrence following drug treatment and apparent clinical cure affects an estimated 700,000 people annually is increasingly associated with relapse of initial Mycobacterium tuberculosis (Mtb) infection. Cellular immunity by T helper (Th) cells, including Th17 populations important during active TB. The contribution other Th to immune pressure Mtb clearance TB chemotherapy poorly understood. We used Mtb-HN878 for a paucibacillary model infection in WT, IL17RA-KO, second study using WT conditional Th17-KO (CD4-Cre-RORγt flox/flox) mice identify the cellular sources protective role IL-17 therapy. Assessment disrupted lung multi-parameter flow cytometry demonstrated that expand TB, retract after therapy, subsequently display moderate re-expansion relapse. Flow cytometric analysis also revealed expansion contraction +cells among both non-lymphocyte CD3 −lymphocyte active, post-drug, phase Compared IL-17RA-KO had greater mycobacterial burden These results demonstrate critical cells signaling protection against regrowth chemotherapy. Further, it suggests lymphoid non-lymphoid innate system contribute IL-17-mediated NHI grant R01AI147948