The JJ319 monoclonal antibody specifically recognizes CD28, which is expressed on virtually all T lymphocytes bearing αβ T-cell receptors (TCR), on most γδ TCR-bearing T cells, and on a subset of NK cells. In the thymus, CD28 expression is developmentally regulated during the maturation of αβ TCR-bearing T cells. CD28 is a costimulatory receptor required for activation of T cells; its ligands include CD80 (B7-1) and CD86 (B7-2). Soluble JJ319 mAb costimulates the proliferative responses and IL-2 production of CD4+ and CD8+ T cells activated by anti-αβ-TCR mAb R73 (Cat. no. 554910). The alternate anti-rat CD28 mAb JJ316 (Cat. No. 554992) is capable of directly stimulating T cells in vitro and in vivo.
The antibody was conjugated to BD Horizon BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).