Human lymphatic vessels express several leukocyte adhesion molecules. The study here investigated the expression of three junctional adhesion molecules (JAM) which are a newly reported glycoprotein family of adhesion molecules on human lymphatic endothelium. In this study, JAM-1 and JAM-3 but not JAM-2 were detected in cultured human neonatal dermal lymphatic endothelial cells (LEC) at the gene and protein levels by microarray, RT-PCR, real-time PCR, and immunohistochemical analysis. The JAM-1 and JAM-3 expression was not altered in the TNF-alpha-treated LEC or in the untreated cells. In human tissue, the expression of JAM-1, and the expression of JAM-1, JAM-2, and JAM-3 were observed in collecting lymphatic vessels of uninflamed small intestine, and in initial lymphatics of inflamed tongue and uninflamed gingival tissue. It is thought that JAM-2 mRNA could be produced in mature vascular endothelium but not in cultured cells, and that human intestinal and oral lymphatic vessels usually express JAM-1, JAM-2, and JAM-3. There were initial lymphatics simultaneously expressing JAM-1, JAM-2, and JAM-3 in the mucosal connective tissue papillae of gingival tissue. The three JAM expressions on the lymphatic endothelium may contribute to both seal the cell-cell contact at interendothelial junctions and also allow lymphocytes to transmigrate into lymphatic vessels from tissue, independent of inflammatory cytokines.