Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 15, 1999
Publication Date: 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 prepared by digestion of proteins from the organism appears to provide better protection of pigs against dysentery than preparations of the whole organism which were used previously. However, 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 compared to the response of pigs vaccinated with the whole cell preparation. This study showed a unique immune response of one subset of white blood cells isolated from the pigs vaccinated with the recently developed vaccine or from pigs vaccinated with a whole cell preparation. The results from this study indicate that this subset of white blood cells are likely important in providing protection from swine dysentery.
Serpulina hyodysenteriae infection of pigs (swine dysentery) causes a mucohemorrhagic diarrhea resulting in significant economic losses for producers. A commercial vaccine consisting of a proteinase-digested bacterin has shown efficacy in the reduction of disease due to S. hyodysenteriae. Vaccines consisting of whole cell bacterins, however, generally fail to protect pigs from disease. In the present study, cellular immune responses induced by a proteinase-digested bacterin were compared to responses induced by a whole cell sonicate antigen preparation. In addition, usage of either squalene or Freund's incomplete adjuvants in combination with each antigen preparation was also compared. Both antigen preparations indcued significant cellular immune responses as measured by in vitro (IFN-gamma production and T cell proliferation) and in vivo methods (DTH responses). No significant differences were detected in pro- liferative, interferon-gamma (IFN-gamma), or delayed type hypersensitivity (DTH) responses by pigs receiving either adjuvant or antigen preparation. T cells (CD3**+), but not B Cells, from vaccinated animals proliferated in response to in vitro stimulation with S. hyodysenteriae antigen. CD8**+ (single positive and CD4/CD8 double positive) and gamma delta**+ T cells were particularly responsive. In addition, high percentages of both CD8 single positive and CD4/CD8 double positive cells were detected in antigen- stimulated cultures. These findings demonstrate the unique sensitivity of porcine CD8**+ T cells to priming for recall response by vaccination with a proteinase-digested S. hyodysenteriae bacterin.