HETEROGENEITY OF HUMAN FACTOR-VIII .1. CHARACTERIZATION OF FACTOR-VIII PRESENT IN SUPERNATANT OF CRYOPRECIPITATE

  • 1 January 1978
    • journal article
    • research article
    • Vol. 91  (1) , 32-46
Abstract
Recent observations suggest that plasma F [factor] VIII consists of a series of molecules with different MW. Sup F VIII [supernatant plasma of cryoprecipitate] may represent the molecules with relatively low MW but the molecules with the highest MW appear in cryo F VIII [factor VIII present in cryoprecipitate] Sup F VIII was associated with VIII:C [factor VIII coagulant activity] and VIIIR:Ag [factor VIII related antigenic activity] but ristocetin cofactor activity was lacking. Although the immunoprecipitation characteristics of sup F VIII with rabbit antifactor VIII were different from those of cryo F VIII, immunological identity was observed in immunodiffusion and crossed immunoelectrophoresis. In 0.8 M NaCl sup F VIII dissociated into VIIIR:Ag of relatively high MW and VIII:C of low MW. No indications were obtained that the presence of sup F VIII was the result of proteolytic degradation of factor VIII. VIII:C of sup F VIII was more labile in vitro than VIII:C in plasma. It could be activated by traces of thrombin in a way similar to plasma F VIII. In patients with classic von Willebrand''s disease relatively more VIII:C remained in the supernatant after cryoprecipitation of plasma.