Picture of an HLA-DQ molecule presenting an antigenic peptide for a T-cell receptor

HLA-DQ molecules

The human leukocyte antigen (HLA) system (also called the major histocompatibility complex; Mhc) is a large gene region on the short arm of chromosome 6. It contains over 100 genes and most of these genes code for proteins involved in the immune system. The function of the immune system is to defend the body against foreign pathogens (such as bacteria, viruses and malignant cells). This requires a system which can distinguish between self and non-self, and some of the proteins in the HLA system is a part of this system. Foreign invaders (antigens) are cut into small peptide pieces, which are then displayed bound to HLA molecules on the surface of cells. HLA molecules with bound peptides are recognized by T-lymphocytes and immune reactions against intruders are generated. The following pages are focused on the antigen-presenting HLA class II DQ proteins. HLA-DQ proteins are expressed primarily on antigen-presenting cells (APC) and presents antigens for CD4+ T lymphocytes. HLA-DQ molecules are highly polymorphic and some of the DQ alleles have been associated with an increased risk for several autoimmune diseases.

HLA-DQ molecules

Contents

An historical introduction to the Mhc

Organisation of the Mhc

Structure of HLA-DQ proteins

Functions and characteristics of HLA-DQ proteins

References

Acknowledgments