The BB7.1 monoclonal antibody specifically recognizes the Human Leukocyte Antigen-B7 (HLA-B7) alpha subunit. The HLA-B7 alpha chain can noncovalently heterodimerize with β2-microglobulin to form a Major Histocompatibility Complex (MHC) class I B7 antigen that is involved in antigen presentation to CD8+ T cells or might serve as an NK cell receptor ligand. HLA-B7 is a serotype that identifies the more common HLA-B (HLA-B*07) encoded gene products which are expressed on nearly all nucleated cells of HLA-B7-positive individuals. B7 is a risk factor for cervical cancer, sarcoidosis, and some spondylarthropathies. The BB7.1 antibody can be used to distinguish false HLA-B27-positve staining when used in conjunction with some HLA-B27 antibodies that crossreact with HLA-B7. Although highly specific, the BB7.1 antibody can reportedly crossreact with HLA-B42 and HLA-B81 antigens.
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).