Resistin (resistance-to-insulin, RETN) is a 10 kDa member of a small family of secreted cysteine-rich peptide hormones which also known as adipocyte-specific secretory factor (ADSF) and found in inflammatory zone 3 (FIZZ3). Human Resistin precursor is 108 amino acids (aa) in length. It contains an 18?aa signal sequence plus a 90?aa mature region. These molecules purportedly play some role in inflammation, glucose metabolism, and angiogenesis. Besides, Toll Like Receptor 4 (TLR4) has been identified as an interactor of RETN, thus a binding ELISA assay was conducted to detect the interaction of recombinant human RETN and recombinant human TLR4. Briefly, RETN was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to TLR4-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-RETN pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 μL stop solution to the wells and read at 450/630nm immediately. The binding activity of RETN and TLR4 was shown in Figure 1, the ED50?for this effect is 5.13 ug/mL.