title: A cleavage-associated neoantigenic marker for a gamma chain site in the NH2-terminal aspect of the fibrinogen molecule.
abstract: The E fragment, derived from the NH2-terminal aspect of fibrinogen by plasmin cleavage (fg-E), possesses two generically distinct sets of antigenic expressions. The major set of antigens is expressed by the parent molecule as indicated by the capacity of a major subpopulation of antibodies present in antiserum to fg-E and reactive with fg-E to: (a) react with fibrinogen, and (b) be specifically absorbed by fibrinogen but appears following proteolysis with plasmin. These cleavage associated neoantigens (fg-E-neo) specifically react with a minor subpopulation of antibodies present in antiserum to fg-E.E fragments isolated after varying exposures to plasmin all expressed fg-E-neo, but early E fragments exhibited quantitatively less neoantigenic expression than more extensively degraded E fragments. The entire fg-E-neo expression is recovered on a single isolated constituent chain of the E fragment, and immunochemical analysis with antiserum to the isolated constituent chain-bearing fg-E-neo identifies it as a derivative of the gamma chain constituent, exhibits marked stability to physicochemical denaturation and enzymatic degradation. These properties suggest that the neoantigen may be associated with a specific amino acid sequence which is exposed by the cleavage process. The identification and localization of fg-E-neo provides a specific molecular marker site for the characterization of structural and conformational changes associated with catabolism and function of fibrinogen.
mesh_terms: D000818:Animals; D000937:Antigen-Antibody Reactions; D001666:Binding Sites, Antibody; D002918:Chymotrypsin; D000939:Epitopes; D005340:Fibrinogen / Q000276:immunology; D005341:Fibrinolysin; D006146:Guanidines; D006358:Hot Temperature; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000302:isolation & purification; D011489:Protein Denaturation; D011817:Rabbits / Q000276:immunology; D014357:Trypsin
chemical_list: D000939:Epitopes; D006146:Guanidines; D010446:Peptide Fragments; D005340:Fibrinogen; D002918:Chymotrypsin; D014357:Trypsin; D005341:Fibrinolysin