Corynebacterium pseudoWHAT? A Mouse Model for Equine Corynebacterium pseudotuberculosis Vaccine Development
Authors:Kristina Geiger, Megan Sumida
- Karen Molinder, Faculty Mentor, Occidental College
- Roberta Pollock, Faculty Mentor, Occidental College
Pigeon fever is an equine disease caused by the bacterium Corynebacterium pseudotuberculosis. It has three manifestations: external abscesses on the pectoral region, internal abscesses, and/or ulcerative lymphangitis. We seek to understand the equine immune response to this bacterium in order to create a successful vaccine. We use a mouse model to test potential vaccines made of different formalin inactivated protein components of C. pseudotuberculosis. Mice are an ideal model for the disease because they are genetically identical, easier to handle than horses, and require much less total protein for vaccine development. Our lab employs two inbred strains of mice: BALB/c and C57Bl/6. BALB/c mice tend to show a higher Th2 response to antigens, while C57Bl/6 mice tend to show a higher Th1 response. To test vaccine viability, the mice are immunized and then challenged with live bacteria. Using Enzyme-Linked Immunosorbent Assay, antibody levels in serum are measured and disease severity is determined. Preliminary ELISAs from our fifth mouse experiment showed that mice immunized with the PLD vaccine responded well to PLD but not to cell lysate. Another approach to vaccine development is identifying individual antigenic proteins to use in a vaccine preparation. Thirteen hybridoma cell lines made from a mouse immunized with cell lysate have been tested: these hybridoma cells produce a single type of antibody. These monoclonal antibodies were generated and tested by ELISA and Western Blot for reactivity to C. pseudotuberculosis proteins. Using these antibodies, we also detected proteins that induce an immune response in both horses and mice by Western Blot analysis. Two of our anti-cell lysate hybridoma cell lines bound to a single antigenic protein that can be evaluated for efficacy in a vaccine. Testing antigenic proteins for a protective immune response will allow us to develop an effective vaccine.