Description: The TL2.1 monoclonal antibody reacts with human Toll-like receptor 2 (TLR2). To date, at least ten members of the Toll family have been identified in human. This family of type I transmembrane proteins is characterized by an extracellular domain with leucine-rich repeats and a cytoplasmic domain with homology to the type I IL-1 receptor. Two of these receptors, TLR2 and TLR4, are pattern recognition receptors and signaling molecules in response to bacterial lipoproteins and have been implicated in innate immunity and inflammation. TLR2 is expressed by peripheral blood monocytes and is responsible for distinguishing different pathogens. TL2.1, a blocking antibody, has been used to study the role of TLR-2 as a pattern recognition receptor in microbial lipoprotein/lipopeptide induced cytokine production from human peripheral blood mononuclear cells. TL2.1 has been reported to immunoprecipitate human TLR2 (~90 kDa) from PBMC and HMEC.