Vanin-2 (VNN2)?is a glycosylphosphatidylinositol (GPI)-anchored ectoenzyme that plays crucial roles in inflammation and oxidative stress responses. As a member of the vanin family, it exhibits pantetheinase activity, converting pantetheine into cysteamine and pantothenic acid (vitamin B5). VNN2 is highly expressed in immune cells, particularly neutrophils, where it modulates cellular adhesion and migration during inflammatory processes. Recent studies highlight its involvement in neutrophil recruitment to inflammatory sites and its potential as a biomarker for various inflammatory diseases. The enzyme's activity influences glutathione metabolism, thereby regulating redox homeostasis in immune responses.Besides,VNN2 directly binds to Integrin Beta 2 (CD18) on leukocytes, facilitating their adhesion and transendothelial migration during inflammation.Thus a functional binding ELISA assay was conducted to detect the interaction of recombinant human VNN2 and recombinant human CD18. Briefly, VNN2 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to CD18-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-VNN2 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 recombinant human VNN2 and recombinant human CD18 was shown in Figure 1, the EC50?for this effect is 0.009 μg/mL.