Influenza A virus infection-induced macroautophagy facilitates MHC class II-restricted endogenous presentation of an immunodominant viral epitope

Abstract

CD4+ T cells recognize peptides presented by major histocompatibility complex class II molecules (MHC-II). These peptides are generally derived from exogenous antigens. Macroautophagy has been reported to promote endogenous antigen presentation in viral infections. However, whether influenza A virus (IAV) infection-induced macroautophagy also leads to endogenous antigen presentation through MHC-II is still debated. In this study, we show that IAV infection leads to endogenous presentation of an immunodominant viral epitope NP311–325 by MHC-II to CD4+ T cells. Mechanistically, such MHC-II-restricted endogenous IAV antigen presentation requires de novo protein synthesis as it is inhibited by t..