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™ BV650 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor® 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.