Divergent Roles of Autophagy in Virus Infection

Chiramel, Abhilash I.; Brady, Nathan R.; Bartenschlager, Ralf

The role of autophagy is not limited to the innate immune response, but also plays a major role in the adaptive immune response by processing and delivering antigens for presentation in complex with MHC-I and MHC-II molecules [63] (Figure 3) . Typically, MHC-I molecules present endogenous antigens that are degraded by the proteasome and transported into the ER, where they are loaded onto MHC-I molecules. After transport to the cell surface, peptide-loaded MHC-I stimulates a CD8+ T-cell response responsible for controlling infections [64] . MHC-II molecules present exogenous antigenic peptides that are processed by lysosomal degradation. Peptides are loaded onto MHC-II and transported to the cell surface to stimulate a CD4+ T-cell response [64] . Notably, exogenous antigens can also be presented on MHC-I molecules to mediate a CD8+ T-cell response by a mechanism termed - [65] . This is found primarily with dendritic cells, macrophages and B lymphocytes and plays a major role in the immune defense against numerous viral and bacterial infections.