J. S. Hogan1, J. Lin, and K. L. Smith
The Ohio State University Department of Animal Sciences
Purified bovine and mouse antibodies directed against the iron receptor protein FepA inhibited growth of coliform bacteria in vitro. Growth of Escherichia coli was significantly inhibited by the addition of monoclonal antibody to synthetic medium containing apolactoferrin. Antigenic variation in the ferric enterobactin binding site resulted in a low percentage of Klebsiella pneumoniae isolates that were inhibited by the monoclonal antibody. Purified bovine immunoglobulin G (IgG) directed against FepA inhibited growth of E. coli but not K. pneumoniae isolates cultured in dry cow secretion. Exogenous ferric chloride completely reversed the inhibitory effects of antibodies and lactoferrin. Immunoglobulin G from cows immunized with FepA apparently inhibited the growth of coliform bacteria by interfering with the binding of ferric enterobactin complex to the cell surface receptor FepA.
1 For more information, contact at: The Ohio State University, Ohio Agricultural Research and Development Center, 302 Pounden Hall, 1680 Madison Avenue, Wooster OH 44691, 303-263-3801, Fax 330-263-3949, e-mail: hogan.4@osu.edu