Antigen Processing for MHC Class II Presentation via Autophagy

Christian Münz

doi:10.3389/fimmu.2012.00009

Abstract

T cells recognize proteolytic fragments of antigens that are presented to them on major histocompatibility complex (MHC) molecules. MHC class I molecules present primarily products of proteasomal proteolysis to CD8+ T cells, while MHC class II molecules display mainly degradation products of lysosomes for stimulation of CD4+ T cells. Macroautophagy delivers intracellular proteins to lysosomal degradation, and contributes in this fashion to the pool of MHC class II displayed peptides. Both self- and pathogen-derived MHC class II ligands are generated by this pathway. In addition, however, recent evidence points also to regulation of extracellular antigen processing by macroautophagy. In this review, I will discuss these two aspects of antigen processing for MHC class II presentation via macroautophagy, namely its influence on intracellular and extracellular antigen presentation to CD4+ T cells.

Highlights

Christian Münz*T cells recognize proteolytic fragments of antigens that are presented to them on major histocompatibility complex (MHC) molecules
T cells recognize antigenic fragments presented to them by major histocompatibility complex (MHC) molecules
invariant chain (Ii) is degraded in MHC class II containing compartments (MIICs) by lysosomal hydrolysis, and its last remnant the CLIP peptide is released from the MHC class II peptide binding groove under the influence of the HLA-DM chaperone, which is negatively regulated by HLA-DO in some cell types

Summary

Christian Münz*

T cells recognize proteolytic fragments of antigens that are presented to them on major histocompatibility complex (MHC) molecules. MHC class I molecules present primarily products of proteasomal proteolysis to CD8+ T cells, while MHC class II molecules display mainly degradation products of lysosomes for stimulation of CD4+ T cells. Macroautophagy delivers intracellular proteins to lysosomal degradation, and contributes in this fashion to the pool of MHC class II displayed peptides. Both self- and pathogen-derived MHC class II ligands are generated by this pathway. I will discuss these two aspects of antigen processing for MHC class II presentation via macroautophagy, namely its influence on intracellular and extracellular antigen presentation to CD4+ T cells

INTRODUCTION

MHC class II antigen processing by autophagy

Findings

CONCLUSION AND OUTLOOK