Characterization of a CA (II)-independent monoclonal antibody that lacks reactivity with gla-domainless human factor VII

Eight murine monoclonal antibodies to human factor VII have been produced and characterized. As tested by direct ELISA, all antibodies bound to immobilized factor VII and this interaction did not require Ca(II). On immunoblotting three antibodies reacted only with native factor VII and activated factor VII (rFVIIa), two with native factor VII, activated factor VII and with the light chain of reduced activated factor VII and three with reduced activated factor VIIa (light chain) only. When coupled to Sepharose five antibodies were capable of immunodepleting factor VII from normal plasma and inhibited coagulant activity with varied potencies. Among these antibodies, one (10C12.2) had peculiar characteristics, lacking reactivity with Gladomainless FVII and with the Ca(II)-dependent conformation. This antibody has been used to develop a two-site ELISA which appears to measure native factor VII but not poorly carboxylated, inactive forms of the molecule.