INHIBITION OF CELL-ADHESION BY PROTEOLYTIC FRAGMENTS OF TYPE-V COLLAGEN

Type V collagen inhibits the cell-substratum adhesion of many types of cells. In this study, inhibitory effects of type V collagen on the ad hesion of mouse melanoma B16-F10 cells to fibronectin, laminin and vit ronectin were investigated. When the culture dishes were coated with a mixture of fibronectin and type V collagen, adhesion of the cells was inhibited by 50% at a fibronectin/collagen molar ratio of 10/1. At a similar molar ratio, adhesion of the cells to laminin was inhibited mo derately, but that to vitronectin was not significantly affected. Type V collagen added into culture medium was less effective in inhibiting cell adhesion. The antiadhesive activity of type V collagen was parti ally retained in the alpha1 (V) chain of heat-denatured collagen. The alpha1 (V) chain was split into two large fragments, 90 kDa and 60 kDa , by limited digestion with Staphylococcus aureus V8 proteinase. The 9 0-kDa fragment, which was derived from the C-terminal half of the alph a1 (V) chain, inhibited the cell adhesion more profoundly than alpha1 (V). However, little fibronectin bound to the 90-kDa fragment, while f ibronectin bound to the 60-kDa fragment, which was less antiadhesive t han the 90-kDa fragment, with the same extent as alpha1 (V). We theref ore concluded that the antiadhesive effect of type V collagen was not due to its specific binding to the fibronectin molecule.