The RR4-7 antibody specifically reacts with the Vβ 6 T-Cell Receptor (TCR) of mice having the a (e.g., C57BR, C57L, SJL) and b (e.g., A, BALB/c, CBA/Ca, C3H/He, C57BL, DBA/1) haplotypes of the Tcrb gene complex. The Tcrb-V6 gene locus is deleted in mice having the c (e.g., RIII) haplotype. Vβ 6 TCR-bearing T lymphocytes are clonally eliminated in mice expressing superantigen encoded by Mtv-7 (Mls-1[a], Mls[a]) endogenous provirus (e.g., AKR, CBA/J, C58, DBA/2, NZB), or Mtv-43 endogenous provirus (e.g., MA/MyJ). Exogenous MMTV-SW, as well as endogenous Mtv-44-encoded superantigen (e.g., NZW), also causes incomplete elimination of Vβ 6 TCR-expressing T cells. Plate-bound RR4-7 antibody activates Vβ 6 TCR-bearing T cells, soluble RR4-7 mAb blocks in vitro proliferation and cytolytic activities of Vβ 6 TCR-bearing T-cell clones, and injection of the antibody results in in vivo depletion of Vβ 6 TCR-bearing T cells.
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.