The G42-8 monoclonal antibody specifically recognizes the alpha subunit (32 kDa) of CD8αα homodimer or CD8αβ heterodimer. The CD8 molecule binds to HLA class I molecules during interaction of CD8+ T cells with antigen-presenting cells or target cells. CD8 is expressed on T cytotoxic/suppressor cell populations. G42-8 stains approximately 13-48% of peripheral blood lymphocytes and 80% of thymocytes, as well as a subset of NK cells. This antibody is useful in detecting CD8+ T cells when using DimerX I reagents.
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.