Open AccessLocalization of a factor VIII-inhibiting antibody epitope to a region between residues 338 and 362 of factor VIII heavy chain.
Author(s) -
Jerry Ware,
John R. Toomey,
Darrel W. Stafford
Publication year - 1988
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.85.9.3165
Subject(s) - epitope , linear epitope , recombinant dna , microbiology and biotechnology , antibody , epitope mapping , monoclonal antibody , peptide sequence , amino acid , cleavage (geology) , immunoglobulin light chain , chemistry , biology , peptide , biochemistry , gene , genetics , paleontology , fracture (geology)
We have used a recombinant DNA epitope library to localize the binding region of a factor VIII (FVIII) monoclonal antibody that neutralizes coagulant activity. The antibody, C5, has previously been described and has been shown to have a FVIII neutralizing potency of 1488 Bethesda units per mg of purified immunoglobulin. A recombinant DNA epitope library was constructed from short, random FVIII cDNA fragments and immunologically screened with C5 to identify bacteriophage expressing the antigenic determinant. The isolation and characterization of immunoreactive bacteriophage restricted the C5 epitope to the overlapping or shared DNA sequence of nine different clones and corresponded to amino acid residues 338-362 of the mature FVIII peptide. The defined epitope is between the proposed activated protein C cleavage site (Arg-336) and thrombin cleavage site (Arg-372) on the amino-terminal 90-kDa FVIII heavy-chain subunit. The identification of the epitope of an inhibiting anti-FVIII antibody between two critical cleavage sites suggests that this amino acid sequence plays a role in regulating FVIII coagulant activity.