Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/1999
Publication Date: N/A
Citation: N/A Interpretive Summary: Swine dysentery is a diarrheal disease of pigs which results in significant economic losses to swine producers. Although the organism which causes swine dysentery is known, how this disease develops in the large intestine is not well understood. Commercial vaccines have been developed for swine dysentery and are currently in use. A recently developed swine dysentery vaccine appears to provide better protection of pigs against dysentery tha previous vaccines, but how this vaccine works is unknown. The present study was designed to examine the immune response of pigs following intramuscular vaccination with this recently developed vaccine. Vaccination resulted in increased percentages of a specific type of white blood cell and an increase in the levels of a protein produced by white blood cells which is known to be important in enhancing the immune response. This study also showed that the immune response of cells isolated from the pig's large intestine differs from that of cells isolate from blood. In conclusion, these studies show that intramuscular vaccination results in alterations in the immune response which may provide protection from a swine dysentery.
Technical Abstract: Serpulina hyodysenteriae infection of pigs, swine dysentery, causes a mucohemorrhagic diarrhea resulting in significant economic losses to swine producers. The pathogenesis of this disease is poorly understood. Regardless, commercial vaccines have been developed and are in use. Thus, the present study was designed to examine cellular immune responses induced dby parenteral S. hyodysenteriae vaccination. Significant antigen-specific interferon-gamma (IFN-gamma) and blastogenic responses were detected from peripheral blood lymphocytes isolated from vaccinated pigs. However, poor IFN-gamma responses were detected from colonic lymph node lymphocytes from these same pigs despite significant antigen-specific blastogenic responses. In addition, peripheral blood IFN-gamma responses were diminished by either in vitro depletion of CD4 expressing cells or by in vitro treatment with porcine IL-10. Colonic lymph node IFN-gamma responses were not inhibited by treatment with porcine IL-10. Vaccination also resulted in increased percentages of both mucosal and peripheral blood CD8 single positive cells with concurrent decreases in percentages of CD4 single positive cells as compared to percentages of these same populations from non-vaccinated pigs. In conclusion, these studies show that parenteral S. hyodysenteriae vaccination results in cellular immune responses detectable both peripherally (systemic immunity) as well as at the site of infection (mucosal immunity). However, it appears that regulatory mechanisms affecting IFN-gamma production in response to S. hyodysenteriae antigen differ between peripheral and colonic compartments.