Protection of sheep against experimental footrot by vaccination with pili purified from Bacteroides nodosus.
Merino sheep vaccinated with either whole Bacteroides nodosus organisms, a crude surface antigen preparation or highly purified pili (>99% homogeneity) in oil adjuvant, developed significant resistance to artificial footrot infection when compared with unvaccinated control sheep inoculated with saline-in-oil emulsion (Freund;s incomplete adjuvant) alone. The pili-vaccinated sheep generally had higher K-agglutinating antibody titres than sheep vaccinated with whole B. nodosus. These results confirmed the role of B. nodosus pilus protein both as a protective antigen and the K-agglutinogen. Vaccines prepared with Freund;s incomplete adjuvant containing either purified pili, crude pili or B. nodosus whole cells did not produce significantly different injection-site reactions.
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Wallaceville Animal Research Centre, Research Division, Ministry of Agriculture and Fisheries, Private Bag, Upper Hutt.
Skerman
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