The 7D3 monoclonal antibody specifically binds to T cell immunoglobulin mucin 3 (TIM-3) which is also known as, CD366, or T-cell immunoglobulin and mucin domain-containing protein 3 (TIMD-3/TIMD3). CD366 is encoded by the HAVCR2 gene (Hepatitis A virus cellular receptor 2). CD366 is a type I transmembrane glycoprotein and belongs to the human TIM family (along with TIM-1 and TIM-4) within the immunoglobulin superfamily. CD366 is expressed on Th1, Tc1, Th17, Treg, NK T, and NK cells. CD366 is also expressed on dendritic cells, mast cells, monocytes, and macrophages. It is not expressed by Th2 and B cells. CD366 helps maintain peripheral immune tolerance and homeostasis. CD366 regulates macrophage activation and is a negative regulator of Th1 cell function. Crosslinking of cell surface CD366 by binding to Galectin-9 and/or phosphatidylserine appears to play an important role in either positively or negatively regulating leucocyte functions, such as cytokine production or the phagocytosis of apoptotic cells. CD366 may also be useful as an AML stem cell surface marker because it appears to be more highly expressed by AML leukemia stem cells than by normal bone marrow hematopoietic stem cells.
The antibody was conjugated to BD Horizon™ BUV737 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 737-nm. BD Horizon Brilliant BUV737 can be excited by the ultraviolet laser (355 nm) and detected with a 740/35 filter. Due to the excitation of the acceptor dye by other laser lines, there may be significant spillover into channels detecting Alexa Fluor® 700-like dyes (eg, 712/20-nm filter).
Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BUV737 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV737 reagents (eg, CD4 vs. CD45) can have slightly different fluorescence spillover therefore, it may also be necessary to use clone specific compensation controls when using these reagents.