Autophagy and self-defense.

Autophagy is a highly conserved mechanism which is essential for the maintenance of cellular homeostasis in response to cellular stress. Autophagy has been conserved from yeast to humans as a quality control process that is involved in the recognition and turnover of damaged proteins and organelles. It is also a response mechanism to nutrient starvation. In mammals, autophagy is involved in antigen presentation, tolerance, inflammation and protection against neurodegenerative diseases. The decrease of autophagy during aging reduces the removal of damaged organelles and increases the accumulation of waste products in the cells. In this chapter, we review these aspects of autophagy along with their role in self-nonself distinction, their implication in innate and adaptive immune response, and its dysregulation in the pathology of certain inflammatory and autoimmune diseases.