Endogenous antigen presentation by MHC class II molecules |
| |
Authors: | Andrea J Sant |
| |
Institution: | 1. Department of Pathology, Committee on Immunology, University of Chicago, 5841 S. Maryland Avenue MC1089, 60637, Chicago, IL, (USA)
|
| |
Abstract: | T cell recognition of antigen requires that a complex form between peptides derived from the protein antigen and cell surface
glycoproteins encoded by genes within the major histocompatibility complex (MHC). MHC class II molecules present both extracellular
(exogenous) and internally synthesized (endogenous) antigens to the CD4 T cell subset of lymphocytes. The mechanisms of endogenous
antigen presentation are the subject of this review. Isolation and amino acid sequencing of peptides bound to the class II
molecule indicate that a very high proportion (70–90%) of the total peptides presented by the class II molecule are in fact
derived from the pool of proteins that are synthetized within the antigen-presenting cell (APC). This type of sequence information
as well as the study of model antigens has indicated that proteins expressed in a diversity of intracellular sites, including
the cell surface, endoplasmic reticulum and cytosol can gain access to the class II molecule, albeit with different efficiencies.
The main questions that remain to be answered are the intracellular trafficking patterns that allow colocalization of internally
synthesized antigens with the class II molecule, the site(s) within the cell where peptide: class II molecule complex formation
can take place and whether presentation of ‘foreign’ as well as ‘self’ antigens takes place by mechanisms that vary from one
cell type to another or that vary with the metabolic state of the APC. If such variability exists, is would imply that the
array of peptides displayed by class II molecules at the cell surface has similar variability, a possibility that would impact
on self tolerance and autoimmunity. |
| |
Keywords: | Major histocompatibility complex class II Antigen processing Intracellular trafficking Antigen-presenting cell Invariant chain |
本文献已被 SpringerLink 等数据库收录! |
|