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™ BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.