The J43 monoclonal antibody specifically recognizes CD279 which is also known as PD-1 (programmed death-1). CD279 is a 50-55-kDa glycoprotein encoded by the Pdcd1 gene of the CD28 family of the Ig superfamily. The expression of Pdcd1 mRNA and PD-1 protein is tightly regulated. PD-1 is transiently expressed on CD4-CD8 thymocytes, it is upregulated on some cell lines upon induction of apoptosis, it is induced on thymocytes and splenic T and B lymphocytes after stimulation through their antigen receptors, and it is induced on activated myeloid cells. In addition, Pdcd1 mRNA is transiently expressed in developing B lymphocytes at the pro-B-cell stage. The presence of an ITIM (Immunoreceptor Tyrosine-based Inhibitory Motif) on PD-1's intracytoplasmic region and the development of splenomegaly and breakdown of peripheral tolerance in PD-1[-/-] mice suggest that PD-1 is involved in the negative regulation of immune responses. The PD-1 ligands, B7-H1 (also known as PD-L1, CD274) and B7-DC (PD-L2, CD273), are members of the B7 family of the Ig superfamily. The J43 antibody blocks the binding of PD-1 to its two ligands.
The antibody was conjugated to BD Horizon BUV395 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. With an Ex Max near 348 nm and an Em Max near 395 nm, BD Horizon BUV395 can be excited by the ultraviolet laser (355 nm) laser and detected with a 379/28 filter. This dye has been exclusively developed by BD Biosciences as an optimal dye for use on instruments equipped with the ultraviolet laser and has virtually no spillover into any other detector.