Abstract
Antibodies (Abs) against MHC results in T helper-17 (Th17) mediated immunity against lung self-antigens (SAgs), K-α1 tubulin and collagen V and Obliterative Airway Disease (OAD). Since B cell activating transcription factor (BATF) controls Th17 and autoimmunity, we proposed that BATF may play a critical role in OAD. Anti-H2Kb was administered intrabronchially into Batf−/− and C57BL/6 mice. Histopathology of the lungs on days 30 and 45 following Abs administration to Batf−/− mice resulted in decreased cellular infiltration, epithelial metaplasia, fibrosis and obstruction. There was lack of Abs to SAgs, reduction of SAgs specific IL17 T cells, IL-6, IL-23, IL-17, IL-1β, FGF-6 and CXCL12 and decreased Janus kinase 2, STAT3, and Retinoid-related orphan receptor gamma-T. Further, miR-301a, a regulator of Th17, was reduced in Batf−/− mice in contrast to up regulation of miR-301a and down regulation of PIAS3 in anti-MHC induced OAD animals. We also demonstrate increase in miR-301a in the bronchoalveolar lavage cells from lung transplant (LTx) recipients with Abs to HLA. This was accompanied by reduction in PIAS3 mRNA. Therefore, we conclude that BATF plays a critical role in the immune responses to SAgs and pathogenesis of anti-MHC induced rejection. Targeting BATF should be considered for preventing chronic rejection following human LTx.