Cellular self-cannibalism helps immune cells fight the flu.

CD4 T cells are critical for generating protective immune responses to infection with influenza virus. Although most CD4 T cells react with peptides from extracellular sources, many react with peptides from viral particles synthesized inside cells; however, the pathways employed for processing the latter antigens remain uncertain. Deng et al. provide evidence for a role of autophagy, a cellular self-eating process, in this unconventional antigen processing route, with potential implications for the development of influenza virus vaccines.