Properties of factor VIII/von Willebrand factor in two highly-purified factor VIII concentrates, Hemofil M and Monoclate, using monoclonal antibodies

Properties of F. VIII/vWF in highly-purified factor VIII concentrates were examined using monoclonal antibodies. The F. VIII: C levels obtained with the chromogenic assay agreed with those obtained with the one-stage clotting method. The ratio between F. VIII: Ag and F. VII: C in Hemofil M and Monoclate was 1.09 and 1.34, respectively. The F. VIII: Ag levels assayed by monoclonal ELISAs were the same as those assayed by polyclonal ELISA, except that those assayed by C 5-ELISA tended to be higher. The ratio between F. VIII: Ag and vWF: Ag in Hemofil M and Monoclate was 105 and 45, respectively. Both concentrates lacked the large multimers of vWF and showed the intensification of the satellite bands. SDS-PAGE patterns showed almost no contamination. Immunoblot analysis revealed that F. VIII in both concentrates could react with 6 kinds of monoclonal antibodies to F. VIII. These results suggest that the fundamental structure of F. VIII molecule for coagulant activity in both concentrates are preserved.