The YTH 76.3rMAb is a recombinant monoclonal antibody that specifically recognizes a monomorphic epitope on the extracellular region of the Human Leukocyte Antigen-B (HLA-B) heavy chain. This major histocompatibility complex (MHC) class I antigen is comprised of a polymorphic HLA-B heavy chain, a ~45 kDa type I transmembrane glycoprotein encoded by HLA-B, that is noncovalently associated with the invariant ~12 kDa Beta-2 (β2)-microglobulin light chain encoded by B2M. Hundreds of HLA-B alleles have been reported. HLA-B is expressed on most nucleated cells and leucocytes including specialized antigen presenting cells such as thymic epithelial cells and dendritic cells. HLA-B plays a major role in the MHC-restricted presentation of small peptides, including those derived from self or foreign antigens, that can be bound by TCR expressed on CD8+ thymocytes or T cells leading to either immune tolerance, the maturation of naïve CD8+ T cells, or the activation and differentiation of CD8+ cytotoxic effector T cells or memory CD8+ T cells. HLA-B also functions as a ligand for regulatory CD8 coreceptor molecules and some CD158 molecules that serve as regulatory MHC class I antigen receptors expressed by CD8+ T cells and NK cells. The YTH 76.3rMAb is derived from the hybridoma clone YTH 76.3, with Rat IgG2a, κ isotype. YTH 76.3rMAb has variable region sequences from the original YTH 76.3 clone appended to Rat IgG1 and kappa constant region sequences.
The antibody was conjugated to BD Horizon BUV737 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 737 nm. BD Horizon Brilliant BUV737 can be excited by the ultraviolet laser (355 nm) and detected with a 740/35 nm filter. Due to the excitation of the acceptor dye by the red laser line, there may be significant spillover into red laser detectors with filters in the 700-720 nm range.