The MR9-4 monoclonal antibody specifically recognizes the Vβ 5.1 and Vβ 5.2 T-cell Receptors of strains having the b haplotype (e.g., C57BL) of the Tcrb gene complex. These gene loci are deleted in mice having the a (e.g., C57BR, C57L, SJL, SWR) or c (e.g., RIII) Tcrb haplotype. Vβ5.1 and 5.2 TCR-bearing T lymphocytes are clonally eliminated, either completely or partially, in mice expressing I-E and superantigens encoded by the Mtv-1 (Mls-4a, Mlsc), Mtv-3 (Mlsc), Mtv-8 (Mlsf), Mtv-9 (Etc-1, Mlsf), Mtv-11 (Mlsf), Mtv-13 (Mls-2a, Mlsc), Mtv-27, Mtv44 , and/or Mtv-MAI endogenous provirus (e.g., A, AKR, BALB/c, C3H/He, C58, CBA/Ca, CBA/J, DBA/2, NZB, NZW). Activation of Vβ5 TCR-expressing T cells by this determinant is dependent upon presentation by I-E. Plate-bound MR9-4 antibody activates Vβ5.1 or 5.2 TCR-bearing T cells.
The antibody was conjugated to BD Horizon BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).