Wide distribution of laminin-5 γ2 chain in basement membranes of various human tissues

Laminin 5 (LN5), a heterotrimer of laminin alpha 3, beta 3, and gamma 2 chains, is a laminin isoform which strongly promotes adhesion, migration, and scattering of cells through binding to integrins alpha 3 beta 1, alpha 6 beta 1 and alpha 6 beta 4. To get an insight into the physiological functions of LN5, we prepared a mouse monoclonal antibody to human laminin gamma 2 chain and used it for immunohistochemical analysis of laminin gamma 2 chain in normal human tissues. The basement membranes of various epithelial tissues, such as the skin, lung, small intestine, stomach, kidney and prostate, were immunostained with the anti-laminin gamma 2 chain monoclonal antibody. In addition, the basement membrane of the surface germinal epithelium in the ovary was also positive for laminin gamma 2 chain. These results suggest general roles of LN5 in the anchorage of various types of epithelial cells to the underlying basement membrane and in the expression of their cellular functions. Moreover, deposition of laminin gamma 2 chain around small arteries and veins was observed in the thymus and spleen. This lymphatic organ-specific expression of vascular LN5 might provide a novel function of LN5 in immune responses.