Autophagy in Host Defense Against Viruses

The immune system employs both the adaptive and innate immune responses to combat viral infections. Autophagy, a cytoplasmic lysosomal degradation process, has emerged as an important mechanism in the regulation of multiple aspects of cellular functions in the immune system against viruses. Autophagy may directly contribute to the degradation of viral components. Autophagy can also promote innate immunity and facilitate the processing of viral antigens for the activation of antigen-specific T cells. On the other hand, some viruses have adapted to use autophagy machinery for replication. As an important cellular mechanism to remove damaged or excess protein aggregates and organelles, autophagy plays a critical role in the protection of lymphocytes against stress to prolong their survival, especially the maintenance of long-lived memory cells. Here we discuss the involvement of autopahgy in the regulation of immune responses against viral infections, with emphasis on the roles for autophagy in the protection of immunological memory.