Screening and characterization of monoclonal antibodies to the surface antigens of Listeria monocytogenes serotype 4b |
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Authors: | M. Lin S. Armstrong J. Ronholm H. Dan M.-E. Auclair Z. Zhang X. Cao |
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Affiliation: | Canadian Food Inspection Agency, Ottawa Laboratory Fallowfield, Ottawa, Ontario, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada; Institute for Microstructural Science, National Research Council Canada, Ottawa, Ontario, Canada; Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, Ontario, Canada |
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Abstract: | Aims: This study aims to develop and characterize monoclonal antibodies (Mabs) with high specificity and affinity for surface antigens of an epidemiologically important serotype 4b of Listeria monocytogenes . Methods and Results: Hybridoma clones were derived from B lymphocytes of mice immunized with L. monocytogenes serotype 4b and screened against this strain by an enzyme-linked immunosorbent assay. Twenty-nine clones secreting Mabs reactive with formalin-killed bacteria were obtained; 15, 8, 5 and 1 Mabs were immunoglobulin subclasses IgG2a, IgG2b, IgM and IgG1, respectively. Immuofluoresence or immunogold labelling demonstrated all except five IgM and one IgG2a Mabs bound to the surface of a live L. monocytogenes serotype 4b. The majority of the 23 surface-binding Mabs recognized linear epitopes on a 77-kDa protein. These surface-binding Mabs exhibited little or no cross-reactivity with non-4b serotypes (1/2a, 1/2b, 3a, etc.) of L. monocytogenes , five other Listeria species, Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium. Conclusions: The Mabs recognizing a 77-kDa surface protein are novel antibodies with specificity and affinity for L. monocytogenes serotype 4b. Significance and Impact of the Study: These anti-77 kDa surface protein Mabs may be explored as reagents for the development of Mabs-based diagnostic immunoassays for L. monocytogenes serotype 4b strains. |
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Keywords: | foodborne bacterial pathogens Listeria monocytogenes serotype 4b monoclonal antibodies surface proteins |
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