Serological identification of endothelial antigens predominantly recognized in Kawasaki disease patients by recombinant expression cloning

We showed IgG immune response against endothelial antigens in sera obtained from convalescent Kawasaki disease (KD) patients after recovery from the disease during the follow-up period using serological analysis of recombinant cDNA expression library (SEREX) methodology. We identified 46 antigens represented by 69 clones by immunoscreening of a cDNA expression library from tumor necrosis factor-α (TNFα) treated human umbilical vein endothelial cells (HUVEC) with sera from 4 KD patients. They included ubiquitin pathway proteins, transcriptional factors, signal transduction molecules, metabolic enzymes, cytoskeletal proteins, an adhesion molecule, and a cell cycle protein. By serological survey using phage plaque assay, sera from 5 non-KD patients were rarely reactive with the antigens. Among the antigens, tropomyosin was most frequently isolated (18 of 69 clones). Seventeen of the 18 clones were identified using KD3 serum. The second most frequently isolated antigen was also a cytoskeletal protein, called T-plastin (3 of 69 clones).