Probing plasma clearance of the thrombin-antithrombin complex with a monoclonal antibody against the putative serpin-enzyme complex receptor-binding site.
A high-affinity monoclonal antibody (M27), raised against the human thrombin-antithrombin complex, has been identified and characterized. The epitope recognized by M27 was located to the linear sequence FIREVP (residues 411-416), located in the C-terminal cleavage peptide of antithrombin. This region overlaps, by two residues, the putative binding site of antithrombin for the serpin-enzyme complex receptor. Studies in rats and with HepG2 cells in culture indicated that the Fab fragment of M27 does not block binding and uptake of the thrombin-antithrombin complex, suggesting that this region does not play a major role in the recognition and clearance of the thrombin-antithrombin complex. M27 blocked the ability of antithrombin to inhibit thrombin as well as antithrombin cleavage, both in the presence and absence of heparin.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000990:Antithrombin III / Q000276:immunology / Q000378:metabolism*; D015153:Blotting, Western; D002417:Cattle; D000939:Epitopes; D006801:Humans; D010447:Peptide Hydrolases / Q000097:blood / Q000276:immunology / Q000378:metabolism*; D011817:Rabbits; D015843:Serpins / Q000276:immunology; D013917:Thrombin / Q000037:antagonists & inhibitors; D013997:Time Factors
D000911:Antibodies, Monoclonal; D000939:Epitopes; D015843:Serpins; C046193:antithrombin III-protease complex; D000990:Antithrombin III; D010447:Peptide Hydrolases; D013917:Thrombin