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™ 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).
Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BUV661 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV661 reagents (eg, CD4 vs. CD45) can have slightly different fluorescence spillover therefore, it may also be necessary to use clone-specific compensation controls when using these reagents.