Distribution of plasma fibronectin (cold-insoluble globulin) and components
of the factor VIII complex after heparin-induced precipitation of plasma
DL Amrani, MW Mosesson and LW Hoyer
Factor VIII procoagulant (VIII:C) activity, factor VIII coagulant antigen
(VIII:CAg), von Willebrand ristocetin cofactor (VIIIR:RC) activity, factor
VIII-related antigen (VIIIR:Ag), and plasma fibronectin (CIg;
cold-insoluble globulin) were measured in the heparin precipitable fraction
(HPF) and heparin supernatant fraction (HS) of normal human plasma.
Following heparin induced precipitation, most measurable VIII:C activity
(77% +/- 24%) was recovered in the HS. Although there was little VIII:C
activity (less than 1%) in the HPF, 20% +/- 6.5% VIII:CAg was present as
well as CIg (81% +/- 5.6%). VIIIR:RC activity (72% +/- 12%), and VIIIR:Ag
(34 +/- 5.2%). As assessed by Na dodecyl SO4 glyoxyl agarose
electrophoresis, the multimeric forms of plasma VIIIR:Ag could be resolved
into a series of bands. Larger multimers tended to precipitate with the HPF
whereas the smaller multimers tended to remain supernatant. Plasma from a
subject with congenital afibrinogenemia was also studied. Although the
afibrinogenemic HPF contained CIg, neither VIIIR:RC activity nor VIIIR:Ag
was precipitated. However, both were present in the HPF from
afibrinogenemic plasma to which fibrinogen had been added, suggesting that
they are incorporated in this precipitate because of an affinity for
fibrinogen. The ability of heparin to induce precipitation of CIg while
leaving most VIII:C activity in the supernatant plasma may be useful in the
preparation of procoagulant-rich plasma subfractions, since VIII:C can
subsequently be recovered in good yield by cryoprecipitation.
Volume 59,
Issue 3,
pp. 657-663,
03/01/1982
Copyright © 1982 by The American Society of Hematology
