TLR2 is a member of TLR family which is type I transmembrane proteins with a large number of extracellular leucine-rich repeats (LRRs) and a cytoplasmic Toll/IL-1 receptor (TIR) domain. Human TLR2 is synthesized as a 784 amino acid precursor that contains a signal sequence (aa 1-18), an extracellular domain (aa 19-588) with approximately 20 LRRs, a transmembrane segment (aa 589-609), and a cytoplasmic TIR domain (aa 610-784). The receptor is expressed on a number of cell types including monocytes, dendritic cells, neutrophils, B cells endothelial cells, and hepatocytes. TLR2 functions as part of a heterodimeric complex with either TLR1 or TLR6, and possibly other co-receptors. These complexes recognize lipoproteins and glycolipids from gram-positive and gram-negative bacteria as well as mycoplasma and yeast. TLR2/TLR1 heterodimers bind triacylated lipopeptides, while the TLR2/TLR6 heterodimer preferentially recognizes diacylated lipopeptides. A functional binding ELISA assay was conducted to detect the interaction of recombinant human TLR2 and recombinant human TLR1. Briefly, TLR2 were diluted serially in PBS, with 0.01% BSA (pH7.4). Duplicate samples of 100 μl were then transferred to TLR1-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-TLR2 pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50µL stop solution to the wells and read at 450 nm immediately. The binding activity of TLR2 and TLR1 was shown in Figure 1, and this effect was in a dose dependent manner, the EC50 was 0.21 ug/ml.