Genetic Basis of Resistance to Food-Borne Bacterial Pathogens

Campylobacter jejuni and Eschericha coli are leading causes of food-borne bacterial infections in humans worldwide. Helicobacter hepaticus is a related pathogen that causes liver infections and cancer in susceptible mouse strains. A newly discovered toxin known as cytolethal distending toxin is shared among these pathogens. Identification of the receptor(s)for these microbial toxins in susceptible pigs and susceptible and resistant inbred strains of mice will provide the tools necessary for implementation of genetic selection of livestock resistant to food-borne bacterial diseases, and basic understanding of mechanisms for important bacterial diseases of humans and animals.
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Produce hyperimmune rabbit sera to purified His6-tagged cytolethal distending toxin sub-units A, B and C from each microbe. Use the rabbit hyperimmune sera to identify cytolethal distending toxin target cells by overlay immunohistochemistry binding assay with tissues obtained from all major organs of newborn and adult conventional pigs and from inbred strains of mice of both sexes. Cellular susceptibilities to the toxin will be confirmed by indirect staining of single cell suspensions isolated from selected tissues of pigs and mice with individual or combinations of each sub-unit, rabbit antisera, and fluorescent activated cell sorter analysis. A recombinant flagellar bacterial protein will be included in all assays as a negative control.