Figure 3.

Role of Macroautophagy in Adaptive Immune Responses

Autophagic pathways can deliver antigens for MHC class II presentation. Autophagosomes and LAMP-2a, the transporter associated with chaperone-mediated autophagy, can transport antigens into the MHC-class-II-loading compartment (MIIC). In MIICs, the antigen is processed and loaded onto MHC class II molecules for CD4⁺ T cell stimulation. Activated CD4⁺ T cells can then in turn enhance macroautophagy and autophagosome-lysosome fusion via type II IFN and TNF family members (IFN-γ, TNF, TRAIL, and CD40L). In addition, Th2-polarized CD4⁺ T cells are susceptible to cell death by macroautophagy.