A monoclonal antibody that recognizes a neo-antigen exposed in the E domain of fibrin monomer complexed with fibrinogen or its derivatives: its application to the measurement of soluble fibrin in plasma.
Using urea-solubilized human fibrin monomer as an immunogen, we raised in mice a battery of monoclonal antibodies that reacted with the immunogen but not with urea-treated or native fibrinogen. Although they all failed to react with acid-solubilized fibrin monomer (acid-FM) alone, an antibody designated as IF-43 was found to recognize acid-FM, which was bound with fibrinogen or its derivatives to form a 1:2 complex of soluble fibrin. The epitope for this antibody, thus, appears to be exposed most probably by conformation changes induced in the acid-FM molecule upon formation of the complex. Because IF-43 was able to recognize fibrin-derived plasmic fragment E treated with urea but not the thrombin- and urea-treated amino-terminal disulfide knot of fibrinogen, the presence of the A alpha (52-78) residue segment seems to be prerequiste for the epitope expression. The antibody was found to react with soluble fibrin monomer spiked to normal plasma dose-dependently up to 200 micrograms/mL. By an aggregation assay using latex beads coated with IF-43, we found that concentrations of soluble fibrin monomer in plasma derived from patients with thrombotic diseases were mostly elevated, but not necessarily correlated with those of the D-dimer, reflecting another aspects of the disease. Furthermore, the soluble fibrin monomer in plasma derived from patients with thrombotic diseases was found to be depleted solely of the A peptides, but not the B peptides, based on its subunit polypeptide compositions lacking the beta-chain on immunoblotting.
Soe
G
G
Central Research Laboratories, Iatron Laboratories Inc, Chiba, Japan.
Kohno
I
I
Inuzuka
K
K
Itoh
Y
Y
Matsuda
M
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D001778:Blood Coagulation Disorders / Q000097:blood; D015153:Blotting, Western; D000939:Epitopes; D005337:Fibrin / Q000737:chemistry / Q000276:immunology*; D005340:Fibrinogen / Q000276:immunology*; D006801:Humans; D007841:Latex Fixation Tests; D046911:Macromolecular Substances; D051379:Mice; D008970:Molecular Weight; D010084:Oxidation-Reduction; D011487:Protein Conformation; D012995:Solubility
D000911:Antibodies, Monoclonal; D000939:Epitopes; D046911:Macromolecular Substances; D005337:Fibrin; D005340:Fibrinogen