The 512 monoclonal antibody specifically recognizes a 65-kDa and 55-kDa molecules of the erythrocyte membrane, which are the rat counterpart of mouse Crry/p65, a membrane inhibitor of complement component C3 convertase. Crry/p65 is widely distributed, predominantly expressed on endothelial cells and all circulating cells. This molecule was also detected on immature hepatocytes, systemic endothelial cells, skin fibroblasts, bronchial epithelial cells, bile canaliculi, the Schwann sheath of peripheral nerve fibers, and ependymal cells. Mouse Crry/p65 uses the same mechanisms as human Decay-Accelerating Factor (DAF) and human Membrane Cofactor Protein (MCP) in inhibiting C3 and C5 convertases, but it is not homologous to either DAF or MCP. It has been proposed that Crry/p65 is the mouse genetic homologue of human CR1 (CD35).
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.