The 1082C5 monoclonal antibody (also known as clone 108-2C5) recognizes a shared antigenic determinant present on the extracellular region of Human Leukocyte Antigen-A (HLA-A) heavy chains encoded by a limited number of different HLA-A alleles (HLA-A2, -A3, -A28, -A29, -A30, -A31 and -A33). HLA-A antigens belong to the major histocompatibility complex (MHC) of class I antigens along with HLA-B and HLA-C antigens. HLA class I molecules are heterodimers comprised of an ~40-45 kDa, highly polymorphic transmembrane α heavy chain that is a type I glycoprotein which is noncovalently-associated with an invariant β2-microglobulin (β2m) light chain. The N-terminal extracellular region of the HLA class I heavy chain is comprised of three domains (α1, α2, and α3). The α1 and α2 domains form a closed antigen-binding groove that accommodates 8-10 aa-peptide antigens. β2m non-covalently associates with the α3 heavy chain domain and promotes HLA class I stability. The intralocus HLA-A determinant recognized by the 108-2C5 antibody reportedly involves amino acids residues 76-80 of the HLA-A α1 domain. HLA-A antigens are normally expressed on all nucleated cells. These molecules play central roles in the MHC class I-restricted presentation and cross-presentation of antigens and the regulation of NK and T cell-mediated cytotoxicity that are involved in immune responses to pathogens and tumors as well as tissue allotransplantation.
The antibody was conjugated to BD Horizon BUV661 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 with an Ex Max of 348-nm and an acceptor dye with an Em Max at 661-nm. BD Horizon Brilliant BUV661 can be excited by the ultraviolet laser (355 nm) and detected with a 670/25 filter and a 630 nm LP. Due to cross laser excitation of this dye, there may be significant spillover into channels detecting APC-like emissions (eg, 670/25-nm filter).