Antibody HLA-DR (Clone L243) reacts with the HLADR antigen, which is is present on dendritic cells, monocytes, macrophages, B cells, Haemopoietic precursor cells, activated T and NK cells, as well as some epithelial cells. The mouse monoclonal antibody L243 recognizes specifically HLA-DR molecules, both peptide-loaded and empty. It does not cross react with HLA-DP and HLA-DQ. Clone L243 binds a conformational epitope on HLA-DRα which depends on the correct folding of the αβ heterodimer.