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Inhibition of the activation of hageman factor (factor XII) by eosinophils and eosinophilic constituents
Author(s) -
Ratnoff Oscar D.,
Gleich Gerald J.,
Shurin Susan B.,
Kazura James,
Everson Barbara,
Embury Paula
Publication year - 1993
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.2830420127
Subject(s) - eosinophil cationic protein , eosinophil peroxidase , factor xii , eosinophil , chemistry , major basic protein , peripheral blood mononuclear cell , biochemistry , ellagic acid , microbiology and biotechnology , immunology , peroxidase , in vitro , enzyme , biology , medicine , polyphenol , antioxidant , asthma , coagulation
Abstract Several syndromes characterized by striking eosinophilia may be complicated by thrombosis. The experiments described indicate that, paradoxically, eosinophils and certain of their constituents inhibit the activation of Hageman factor (HF, factor XII). In earlier studies, suspensions of mixed types of granulocytes, other nucleated peripheral blood cells, and platelets inhibited activation of Hageman factor by ellagic acid, glass, and sulfatides. After these cells were sedimented by centrifugation, the supernatant fluids were also inhibitory. No attempt had been made earlier to distinguish among different granulocytic species. In the present study, suspensions of eosinophils and the supernatant fluid after eosinophils had been separated by centrifugation inhibited activation of Hageman factor by ellagic acid. The protein concentration of that amount of supernatant fluid that inhibited activation by about half was 16 μg/ml, approximately the same as had been described for suspensions of peripheral blood mononuclear cells. Activation of Hageman factor by ellagic acid was also inhibited by certain constituents of eosinophils, including eosinophil peroxidase, eosinophil major basic protein and eosinophil cationic protein. Inhibition was not specific for ellagic acid‐induced activation of Hageman factor, as inhibition was also observed with sulfatide‐induced activation. Inhibition was presumably related to neutralization of the negative charge of activators of Hageman factor. Thus, bismuth subgallate, a particulate activator of Hageman factor, was no longer effective after it had been exposed to eosinophil cationic protein. The observations reported here raise the question of whether in vivo eosinophils modulate certain of the defense reactions ascribed to Hageman factor. © 1993 Wiley‐Liss, Inc.