Autophagy and Immune Tolerance.

The immune system plays a critical role in defense against invading pathogens, and its function must be strictly controlled to maintain intracellular homeostasis. Once suffering microbial invasion or receiving danger signals, the immune system initiates the responses timely. After the threat removal, the immune system should be shut down to avoid the harm caused by excessive immune activation. Additionally, the immune system needs to be internally adjusted so that it does not respond to self-antigens to avoid autoimmune diseases. The states of nonresponse in immunity are termed as immune tolerance. Numerous studies indicated that macroautophagy (hereafter named as autophagy) is involved in T cells and B cells related immune tolerance. Recently, more and more researches demonstrated that autophagy is not only capable of nonselective degradation of cellular macromolecular components but also responsible for sorting and transporting autophagic substrates through a group of cargo receptors for selective degradation, which is called as selective autophagy. Recent studies indicated that selective autophagy can effectively regulate the immune tolerance and avoid over-activation of immune response by targeting multiple receptors and effectors of immune cells. In this chapter, we will focus on how autophagy participates explicitly in the adaptive and innate immune tolerance.