The SK10 monoclonal antibody specifically recognizes a class II major histocompatibility complex (MHC) antigen, with a molecular weight of 26 to 34 kDa, distinct from HLA-DR3-5 and HLA-DP5 antigens. Anti-HLA-DQ recognizes a common polymorphic epitope present on HLA-DQ molecules of cells expressing DQw1 and DQw3 (usually associated with DR1, DR2, DR4, DR5, DRw8, DRw9, and DRw10) and absent from DQw2 (usually associated with DR3, and DR7). Therefore, the SK10 antibody not react with cells from DR3 or DR7 homozygotes or DR3/7 heterozygotes. The HLA-DQ antigen is present on approximately 10% of peripheral blood lymphocytes. HLA-DQ reacts weakly with most peripheral blood monocytes and mitogen-stimulated T-lymphocyte blasts. The SK10 antibody reacts with virtually all B-cell lines, some myelomas, and some myeloid leukemias, but only rarely with T-lymphocyte tumors.
The antibody was conjugated to BD Horizon BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).