WIDE DISTRIBUTION OF LAMININ-5 GAMMA-2 CHAIN IN BASEMENT-MEMBRANES OFVARIOUS 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, migra tion, and scattering of cells through binding to integrins alpha 3 bet a 1, alpha 6 beta 1 and alpha 6 beta 4. To get an insight into the phy siological functions of LN5, we prepared a mouse monoclonal antibody t o human laminin gamma 2 chain and used it for immunohistochemical anal ysis of laminin gamma 2 chain in normal human tissues. The basement me mbranes of various epithelial tissues, such as the skin, lung, small i ntestine, stomach, kidney and prostate, were immunostained with the an ti-laminin gamma 2 chain monoclonal antibody. In addition, the basemen t membrane of the surface germinal epithelium in the ovary was also po sitive for laminin gamma 2 chain. These results suggest general roles of LN5 in the anchorage of various types of epithelial cells to the un derlying basement membrane and in the expression of their cellular fun ctions. Moreover, deposition of laminin gamma 2 chain around small art eries and veins was observed in the thymus and spleen. This lymphatic organ-specific expression of vascular LN5 might provide a novel functi on of LN5 in immune responses.