title: A monoclonal antibody, specific for human fibrinogen, fibrinopeptide A-containing fragments and not reacting with free fibrinopeptide A.
abstract: Spleen cells of BALB/c mice, immunized with fragments Y of normal human fibrinogen, were fused with P3 X 63 Ag 8653 myeloma cells. A clone was found which produces monoclonal antibodies (Mab-Y18) of the IgM kappa type. Mab-Y18 is immunoreactive with normal human fibrinogen, and its fragments X, Y, N-terminal disulphide knot, A alpha-chain, and A alpha stretch 1-51. The immunoreactivity with these same fragments disappears upon treatment with thrombin or arvin. This strongly suggests that fibrinopeptide A is an essential component of the Mab-Y18 epitope. This is supported by the finding that Mab-Y18 prolongs the thrombin and arvin clotting times of human fibrinogen by inhibition of the fibrinopeptide A release. More detailed information about the nature of the Mab-Y18 epitope was obtained from studies with genetic variants of human fibrinogen (especially fibrinogen Metz) and with fibrinogens from other mammalian species. These studies show that amino acid residue A alpha 16 (arginine) of fibrinopeptide A is essential for the Mab-Y18 epitope. Mab-Y18 does not react with free fibrinopeptide A.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis / Q000096:biosynthesis; D000915:Antibody Affinity; D000937:Antigen-Antibody Reactions; D002415:Cats; D002417:Cattle; D002999:Clone Cells / Q000378:metabolism; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D005338:Fibrin Fibrinogen Degradation Products / Q000276:immunology*; D005340:Fibrinogen / Q000276:immunology*; D005344:Fibrinopeptide A / Q000276:immunology*; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats; D013045:Species Specificity; D013154:Spleen / Q000166:cytology
chemical_list: D000911:Antibodies, Monoclonal; D005338:Fibrin Fibrinogen Degradation Products; C036129:fibrinogen fragment Y; D005344:Fibrinopeptide A; D005340:Fibrinogen