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™ 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.