Normal Function of HLA Molecules
All animals with white blood cells express a family of cell-surface glycoproteins called major histocompatibility complex (MHC) proteins. In humans, the MHC proteins are called human leukocyte antigen (HLA) molecules. Historically, 6 families of HLA molecules have been identified:
3 MHC class I: HLA-A, -B, -C
3 MHC class II: HLA-DR, -DP, -DQ
Another category of HLA is HLA-D, whose subset, HLA-DM, is critical for loading and editing of peptides on MHC class II molecules. HLA-E, HLA-F and HLA-G are also relevant in immunity and subsequently in human pathology. Chapter 2 discussed the important role that MHC molecules play in immunologic function. HLA genes are also considered human immune response genes because the HLA type determines the capacity of the antigen-presenting cell (APC) to bind peptide fragments and present it, and thus determines T-lymphocyte immune responsiveness.
Excerpted from BCSC 2020-2021 series: Section 9 - Uveitis and Ocular Inflammation. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.