TAX1BP1 a novel player in antigen presentation

CD4$^+$ T lymphocytes play a major role in establishing and maintaining antiviral immunity. They are activated by anti- genic peptides derived from extracellular or newly synthesized (endogenous) proteins presented by the MHC-II molecules. Little is known about the mechanisms leading to endogenous MHC-II-restricted antigen presentation. We recently revealed a novel function of the macroautophagy/autophagy receptor (AR), TAX1BP1, in the presentation of endogenous viral antigens to CD4$^+$ T cells. In this punctum, we will focus on MHC-II-restricted endogenous antigen presentation and the involvement of TAX1BP1 in the biology of MHC-II molecules.