RADIOIMMUNOASSAY OF FIBRINOGEN-FIBRIN DEGRADATION PRODUCTS - ASSAY FOR FRAGMENT E-RELATED NEOANTIGEN - METHODOLOGICAL ASPECTS

E fragment and its antigenically-related degradation products of human fibrinogen (Fg) and/or fibrin (Fb) have been measured in both normal and pathological plasmas by a specific radioimmunoassay (RIA) for the neoantigenic expression of E(Eneo) which is engendered after the plasmic cleavage of Fg or Fb. High titer antisera were produced in rabbits against Fg-E (E derived from Fg). The anti-Fg-E sera harvested were absorbed with a cyanogen bromide-activated immunoadsorbent column coupled with intact Fg. The Fg-absorbed antisera were employed to develop a double antibody RIA which detected < 1 ng/ml of Fg-E and exhibited little cross-reactivity of Fg at 1 mg/ml. This Eneo RIA did not discriminate between Fg-E and Fb-E (E derived from Fb) in the competitive inhibition profile, and hence it measured total Eneo antigens. The displacement curves of normal plasmas generally showed a parallel relationship to the standard which permitted the calculation of normal plasma Eneo immunoreactivity (ca. 15 ng/ml). Considerably higher plasma Eneo immunoreactivities have been observed in patients with consumption coagulopathy. Modifications of the Eneo RIA which permit the attainment of this sensitivity are described. © 1979.