CD44v6 cell surface expression is a common feature of macrophages and macrophage-like cells - implication for a natural macrophage extravasation mechanism mimicked by tumor cells

Soluble CD44standard (sCD44s) and CD44v6 (sCD44v6) cannot only be detected in sera of patients with pancreatic carcinoma but also of healthy blood don ors. To investigate whether sCD44s and sCD44v6 are derived from white blood cells, we stimulated whole blood with phytohemagglutinin and interleukin-2 , which induced expression of CD44v6 only on monocytes. For further investi gations, we used the promyelocytic leukemia cell line HI-60, Only HI-60 cel ls differentiating along the macrophage pathway showed increased expression of CD44s and CD44v6. Furthermore, only macrophages showed increased secret ion of sCD44s and sCD44v6. Our data suggest that CD44s and CD44v6 are commo n adhesion molecules on macrophages and macrophage-like cells. (C) 2000 Fed eration of European Biochemical Societies. Published by Elsevier Science B. V. All rights reserved.