Cutting Edge: Editing of Recycling Class II:Peptide Complexes by HLA-DM

• Published in: The Journal of immunology (1950) Vol. 167; no. 2; pp. 632 - 635
• Main Authors: Pathak, Sulabha S, Lich, John D, Blum, Janice S
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 15-07-2001
• Subjects: Antigen Presentation - genetics; Cell Line; Endosomes - immunology; Endosomes - metabolism; Histocompatibility Antigens Class II - genetics; Histocompatibility Antigens Class II - metabolism; HLA-D Antigens - genetics; HLA-D Antigens - metabolism; HLA-D Antigens - physiology; Humans; Macromolecular Substances; Peptide Fragments - genetics; Peptide Fragments - immunology; Peptide Fragments - metabolism; Protein Transport - genetics; Protein Transport - immunology; RNA Editing - immunology; Transfection
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.167.2.632

HLA-DM catalyzes the exchange and selection of ligands for MHC class II molecules within mature endosomal/lysosomal compartments. Here, evidence is provided that DM edits peptides in early endosomes, thus influencing presentation via recycling class II molecules. Maximal class II-restricted presentation of an albumin-derived peptide, dependent on endocytosis and recycling class II molecules, was observed in cells lacking HLA-DM. DM editing of this epitope was observed in early endocytic compartments as shown using inhibitors of early to late endosomal transport. Editing was tempered by coexpression of HLA-DO, suggesting that DM:DO ratio may be important in guiding epitope editing in early endosomal compartments. Thus, HLA-DM appears to interact with, and edit epitopes displayed by, recycling class II molecules.