The 28-8-6 monoclonal antibody specifically recognizes the H-2K[b] and H-2D[b] MHC class I alloantigens. The reaction with H-2K[b] has been reported to be stronger than that with H-2D[b]. Its recognition of H-2D[b] is dependent upon the presence of β2 microglobulin. Cross-reactivity with an epitope on the N-terminal domains, α1 and α2, of the H-2D[d] MHC class I alloantigen has also been described. Reactivity with other haplotypes (e.g., f, k, p, q, r, s) has not been observed.
The antibody was conjugated to BD Horizon™ BV650 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor® 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.