The C7 monoclonal antibody specifically binds to the low-density lipoprotein (LDL) receptor, a type I membrane protein that is encoded by the LDLR gene. LDL is the major cholesterol-carrying lipoprotein in plasma. Cell surface LDLR controls the level of cholesterol in plasma by binding to and internalizing LDL and transporting it to lysosomes where LDL is degraded, cholesterol is released into the cell, and LDLR is recycled back to the cell surface. Hence LDLR is found in cell-surface and intracellular membranes (eg, clathrin-coated pits, golgi, endosomes, and lysosomes). Expression of LDLR is a marker for in vitro differentiation of hepatocytes from human embryonic stem cells. LDLR is suspected to mediate infections by viruses that associate with lipoprotein in the blood. Mutations in LDLR are largely responsible for Familial Hypercholesterolemia (FH). The C7 monoclonal antibody has been reported to react with bovine and human LDLR, but not LDLRs of mouse, rat, Chinese hamster, rabbit or dog.
The antibody was conjugated to BD Horizon™ BV650 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor® 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.