The KT50 antibody reacts with some members of the Vα 8 T-cell Receptor (TCR) subfamily of mice having the a, b, c, and d haplotypes of the Tcra gene complex (e.g., all strains tested). It recognizes an epitope in the CDR1 of Vα 8.3, but not Vα 8.2, TCR subfamily member, as does the B21.14 mAb (Cat. no. 553374). Site-directed mutagenesis has identified three amino acids which are necessary for antibody reactivity and which are unique to Vα 8.3 among the five functional Vα 8 TCR subfamily members. On a common H-2[k] background, the frequency of Vα 8.3 TCR-bearing T lymphocytes is higher in Tcra[a/a] mice than in Tcra[a/b] mice. Furthermore, studies of congenic strains suggest that CD8+ Vα 8.3 TCR-bearing T lymphocytes undergo negative selection in mice expressing MHC class I antigens of the H-2[d] haplotype.
This antibody is conjugated to BD Horizon™ BV605 which is part of the BD Horizon Brilliant™ Violet family of dyes. With an Ex Max of 407-nm and Em Max of 602-nm, BD Horizon BV605 can be excited by a violet laser and detected with a standard 610/20-nm filter set. BD Horizon BV605 is a tandem fluorochrome of BD Horizon BV421 and an acceptor dye with an Em max at 605-nm. Due to the excitation of the acceptor dye by the green (532 nm) and yellow-green (561 nm) lasers, there will be significant spillover into the PE and BD Horizon PE-CF594 detectors off the green or yellow-green lasers. BD Horizon BV605 conjugates are very bright, often exhibiting brightness equivalent to PE conjugates and can be used as a third color off of the violet laser.