Pathogen-specific antigen target for production of antibodies produced by comparative genomics

Abstract:

Listeria monocytogenes continues to be a major public health risk and there is a need for improved rapid detection methods. New and highly specific L. monocytogenes antibodies are needed to advance current detection and meet the needs of industry. This research compared the L. monocytogenes genome with that of L. innocua (a nonpathogenic species of Listeria) and identified nine surface proteins specific to L. monocytogenes. Protein sequences were collected from the database and properties such as hydropathy profile and transmembrane topology were analyzed using TMpred software. Nine peptide sequences were chosen, and synthetic peptides were made and administered to rabbits for antibody production. All nine antibodies were screened against a panel of L. monocytogenes, nonpathogenic Listeria, and non-Listeria bacteria. Two of the nine antibodies, ie, the Lm404 and LmC639 polyclonal antibodies, showed a specific reaction to L. monocytogenes internalin B and actin polymerization protein, respectively, and were characterized further by enzyme-linked immunosorbent assay, Western blot, and transmission electron microscopy. In Western blot, both antibodies reacted with the targeted protein and did not cross-react with other Listeria spp. The Lm404 polyclonal antibody showed a high reaction with the panel of 41 L. monocytogenes strains while the LmC639 polyclonal antibody showed a weak reaction. Both the Lm404 and LmC639 polyclonal antibodies showed potential for use in immunoassays for specific detection of L. monocytogenes. This study further indicates that comparative genomics could be used to select pathogen-specific antigen for antibody production.

Keywords::

• comparative genomics
• Listeria monocytogenes
• polyclonal antibodies
• internalin B
• actin polymerization protein
• proteomics

Acknowledgments

This research was supported by a cooperative agreement with the Agricultural Research Service of the US Department of Agriculture (1935-42000-072-02G), the Center for Food Safety and Engineering at Purdue University, and the National Cattlemen’s Beef Association.

Disclosure

The authors report no conflicts of interest in this work.