The 21H12 monoclonal antibody specifically binds to TIM-4. TIM-4 is encoded by Timd4 (T cell immunoglobulin and mucin domain containing 4). TIM-4 is also known as Spleen, mucin-containing, knockout of lymphotoxin protein (SMUCKLER). TIM-4 is a single-pass type I membrane transmembrane glycoprotein belonging to the TIM family of the immunoglobulin superfamily. TIM-4 is expressed by macrophages and at low levels by dendritic cells. TIM-4 is a phosphatidylserine receptor that enhances the phagocytosis of apoptotic cells. It can also serve as a receptor for TIM-1, also known as the Hepatitis A virus cellular receptor 1 (Havcr1).
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.