TIM-4 (D3W4F) XP^® Rabbit mAb #75484

T cell Ig- and mucin-domain-containing molecules (TIMs) are a family of transmembrane proteins expressed by various immune cells. TIM-4 is expressed by dendritic cells and macrophages (1). Like TIM-1, TIM-4 is a receptor for phosphatidylserine (2). Interaction of TIM-4 with phosphatidylserine exposed by cells undergoing apoptosis leads to uptake of apoptotic cells (2,3). In this way, TIM-4 regulates adaptive immunity by removing apoptotic antigen-specific T cells following clearance of infection. Peritoneal macrophages from mice deficient in TIM-4 fail to effectively clear apoptotic cells leading to hyperactive T and B cells and autoimmunity (4). In addition, TIM-4 expressed by tumor-associated macrophages and dendritic cells leads to autophagy-mediated degradation of dying tumor cells, resulting in reduced antigen presentation and T cell responses (5). TIM-4 was also identified as a ligand for TIM-1, and interaction between these proteins regulates T cell proliferation (1). Finally, TIM-4 is expressed by a subset of proinflammatory B cells that produce IFN-γ and promote Th1 cell differentiation (6).