Vimentin (VIM) is a type III intermediate filament (IF) protein that is expressed in mesenchymal cells.vimentin is the major cytoskeletal component of mesenchymal cells. Because of this, vimentin is often used as a marker of mesenchymally-derived cells or cells undergoing an epithelial-to-mesenchymal transition (EMT) during both normal development and metastatic progression. Besides, Keratin 20 (KRT20) has been identified as an interactor of VIM, thus a binding ELISA assay was conducted to detect the interaction of recombinant human VIM and recombinant human KRT20. Briefly, VIM were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100μl then transferred to KRT20-coated microtiter wells and incubated for 2h at 37℃. Wells were washed with PBST and incubated for 1h with anti-VIM pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody, wells were aspirated and washed 3 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 450nm immediately. The binding activity of VIM and KRT20 was shown in Figure 1, and this effect was in a dose dependent manner.