Reacts with HLA-DO, a heterodimer formed by DNalpha and DObeta subunits in B cells. DNalpha and DObeta are the products of the non-classical class II genes, HLA-DNA and HLA-DOB, respectively. DO forms tight complexes with DM in the endoplasmic reticulum and is thereby sorted to lysosomal vesicles during antigen processing and presentation. It is tightly associated with DM and it is selectively expressed on antigen-presenting cells, such as B cells, dendritic cells and thymic epithelial cells. DO can enhance the efficiency of peptide loading and has been found to stabilize DM at low pH, preserving its chaperon activity. DO-DM complexes are more efficient than DM in protecting empty DR molecules. Reports describe DO as a co-chaperone of DM.
HLA class II histocompatibility antigen, DO alpha chain; HLA-D0-alpha; lymphocyte antigen; major histocompatibility complex, class II, DN alpha; MHC class II antigen DOA; MHC DN-alpha; MHC DZ alpha