The 8F4H7B7 antibody reacts with Vδ 6.3/2 T-cell Receptor (TCR)-bearing T lymphocytes. Originally defined as a member of the Vδ 6 TCR subfamily, it is now proposed that the C57BL-derived Vδ 6.3 is an allelic variant of Vδ 6.2, found in A/J, AKR, BALB/c, C3H/He, and FVB mice. mAb 8F4H7B7 crossreacts with Vδ 6.4 and possibly Vδ 6.6 in DBA/2 mice, and it also detects a subset of γδ TCR-bearing cells in CBA/J and C57L mice. It does not recognize Vδ 4, Vδ 5, Vδ 6.1, or Vδ 6.5 TCR. A subpopulation of thymocytes expressing Vδ 6.3 or Vδ 6.4 TCR (in C57BL/6 or DBA/2 mice, respectively) and low levels of CD90.2 (Thy-1.2) shares functional and phenotypic characteristics with NK-T cells. Similar δV 6.4 TCRexpressing lymphocytes make up significant proportions of the γδ T-cell populations in the liver and spleen of DBA/2 mice. Furthermore, T lymphocytes bearing Vδ 6.3/2 TCR are found in the skin and intestinal epithelium and may represent a unique T-cell subpopulation with a potential for autoimmune reactivity.
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.