title: Fibronectin and 130-kDa molecule complex mimics snake venom botrocetin-like structure potentially modulating association between von Willebrand factor and vascular vessel wall.
abstract: We established seven hybridomas secreting monoclonal antibodies (MoAbs) against the venom from Bothrops jararaca. Six of them were demonstrated to specifically recognize botrocetin, a venom protein which binds with von Willebrand factor (vWf) and induces platelet agglutination. Two of them, BCT4-3 and BCT115-2 MoAbs, could significantly inhibit botrocetin binding with plasma vWf. BCT4-3 could react slightly with a monolayer of human endothelial cells (ECs), and BCT4-3 binding to ECs was drastically enhanced by the coexistence of human plasma in a dose-dependent manner, indicating that a biological modulator structurally resembling botrocetin is created initially on the EC surface complexed with some plasma proteins. Botrocetin-like components could be immuno-purified only by immobilized BCT4-3, but not by the other immobilized MoAbs, from umbilical vein extracts. Interestingly, the immunoisolated materials were identified to consist essentially of fibronectin (Fn) and a 130 kDa molecule, and this complex bound to vWf in the extracts. Depletion of Fn from plasma decreased BCT4-3 binding to ECs. The epitope of BCT4-3 expressed on the endothelial surface, comprising plasma Fn and the coisolated 130 kDa molecule, is proposed to be a physiological modulator structurally mimicking botrocetin, and essentially supporting vWf-binding to injured endothelium and subsequently to circulating platelets.
authors.affiliation: Takara Shuzo Co., Ltd., Biotechnology Research Laboratories, Shiga.
authors.forename: M
authors.initials: M
authors.lastname: Katayama
authors.forename: S
authors.initials: S
authors.lastname: Nagata
authors.forename: S
authors.initials: S
authors.lastname: Hirai
authors.forename: S
authors.initials: S
authors.lastname: Miura
authors.forename: Y
authors.initials: Y
authors.lastname: Fujimura
authors.forename: T
authors.initials: T
authors.lastname: Matusi
authors.forename: I
authors.initials: I
authors.lastname: Kato
authors.forename: K
authors.initials: K
authors.lastname: Titani
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001665:Binding Sites; D001798:Blood Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002478:Cells, Cultured; D003435:Crotalid Venoms / Q000032:analysis / Q000378:metabolism* / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005353:Fibronectins / Q000494:pharmacology*; D006388:Hemagglutinins / Q000494:pharmacology; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D008970:Molecular Weight; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D014471:Umbilical Veins; D014841:von Willebrand Factor / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D001798:Blood Proteins; D003435:Crotalid Venoms; D005353:Fibronectins; D006388:Hemagglutinins; D014841:von Willebrand Factor; C030961:botrocetin