Entamoeba histolytica: Monoclonal antibody against the beta 1 integrin-like molecule (140 kDa) inhibits cell adhesion to extracellular matrix components

We describe a monoclonal antibody (3C10) against the, beta1 integrin-like m olecule which immunoprecipitates two polypeptides of 140 and 155 kDa from d etergent-soluble extract of Entamoeba histolytica. The 140-kDa polypeptide has been described as a beta subunit of the amoebic fibronectin receptor as it is recognized by an antiintegrin beta1 (human) monoclonal antibody in i mmunoblot assay. The receptor molecules were localized with the 3C 10 monoc lonal antibody in intracellular and surface membranes of E. histolytica tro phozoites by immunofluorescence and immunogold labeling methods. Significan t inhibitions of cell adhesion on extracellular matrix proteins such as fib ronectin (56%) (P < 0.001) and collagen (50%) (P < 0.001) and partial inhib ition on laminin (23%) (P > 0.1) were achieved by the monoclonal antibody. (C) 2001 Academic Press.