The YLI-90 monoclonal antibody specifically reacts with the B6 alloantigen of Ly-49I, an inhibitory receptor which is expressed on subsets of natural killer (NK) cells, NK-1.1+ (or DX5+) T lymphocytes (NK-T cells), and on a population of memory CD8+ T lymphocytes in C57BL/6 mice, but not AKR/J, BALB/c, DBA/1, or SJL mice. The Ly-49 family of NK-cell receptors are disulfide-linked type-II transmembrane protein homodimers with extracellular carbohydrate-recognition domains (CRD). Ly-49I is closely related to Ly-49C[B6] and Ly49C[BALB], and these three alloantigens are recognized by mAb 5E6 (Cat. No. 553277). A Ly-49I[BALB] allele has not been found. The Ly-49 family members are expressed independently, such that an individual NK or T cell may display more than one class of Ly-49 receptor homodimers. Binding of Ly-49I-expressing transfectants to cell lines bearing MHC class I antigens of the b,d, k and s haplotypes was not detected. In contrast, Ly-49I-expressing transfectants were found to weakly bind lymphoblasts of the b, d, k, q, s, and v haplotypes and to strongly bind H-2[r] lymphoblasts. Ly-49I-bearing NK cells may mediate allogeneic and hybrid resistance to transplantation of H-2[d] bone marrow.
The antibody was conjugated to BD Horizon™ BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.