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™ BUV496 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 496-nm. BD Horizon BUV496 can be excited by the ultraviolet laser (355 nm) and detected with a 515/30 nm filter with a 450LP. Due to the excitation of the acceptor dye by other laser lines, there may be significant spillover into the channel detecting BD Horizon V500 or BV510 (eg, 525/40-nm filter). However, the spillover can be corrected through compensation as with any other dye combination.