title: Localization of two epitopes recognized by monoclonal antibody PCG-4 on Clostridium difficile toxin A.
abstract: The toxin A gene of Clostridium difficile contains a 2.5-kb region encoding a series of contiguous repeating units located at the COOH terminus of the molecule. We previously showed that the monoclonal antibody (MAb) PCG-4, which neutralizes the enterotoxic activity of toxin A, binds to epitopes located within these repeating units. In the present study, we subcloned a series of fragments from this portion of the gene. The recombinant peptides expressed from the gene fragments were examined for reactivity with MAb PCG-4 to identify the epitopes involved in binding. Our results showed that MAb PCG-4 recognizes epitopes in amino acid residues 2097 through 2141 and amino acid residues 2355 through 2398.
authors.affiliation: Department of Anaerobic Microbiology, Virginia Polytechnic Institute and State University, Blacksburg 24061.
authors.forename: S M
authors.initials: SM
authors.lastname: Frey
authors.forename: T D
authors.initials: TD
authors.lastname: Wilkins
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001427:Bacterial Toxins / Q000276:immunology*; D016360:Clostridioides difficile / Q000378:metabolism*; D004768:Enterotoxins / Q000276:immunology*; D000939:Epitopes / Q000032:analysis*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D001427:Bacterial Toxins; D004768:Enterotoxins; D000939:Epitopes; D010446:Peptide Fragments; C041348:tcdA protein, Clostridium difficile