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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #333206

Title: Successful protection against heterologous strains of Haemophilus parasuis: the quest for cross protective factors

item EBERLE, KIRSTEN - Orise Fellow
item Nally, Jarlath
item Loving, Crystal
item HAU, SAMANTHA - Iowa State University
item Nicholson, Tracy
item Brockmeier, Susan

Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/4/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Haemophilus parasuis (H. parasuis) infection in swine causes polyserositis, arthritis, and meningitis. Within the 15 serovars, there is a combination of virulent and nonvirulent strains, which has left the pathogenicity and subsequent protection from H. parasuis disease unclear. Here we used bacterins made from two H. parasuis serovar 5 (SV5) strains to examine homologous and heterologous protective antibodies produced during infection and therefore identify possible cross protective factors. Pigs were vaccinated with a H. parasuis bacterin produced from either 265 or Nagasaki, both SV5 strains. Both bacterins protected against challenge with the homologous strains. Surprisingly, pigs given the Nagasaki bacterin were not protected against challenge with virulent 12939, a SV1 strain, while those vaccinated with the 265 bacterin were all protected. Antibody titer, determined by ELISA against both the homologous and heterologous strains using whole cell sonicate, revealed antibody levels similar for both vaccination methods. That is, higher levels of antibody were not the source of protection against 12939. Using an enrichment method with Triton X-114, we isolated the outer membrane proteins (OMPs) of H. parasuis. The OMPs are those predicted to be involved in virulence and antibody protection. A western blot using antiserum from either protected (265 bacterin) or nonprotected (Nagasaki bacterin) pigs against the OMPs of H. parasuis 12939 revealed a stark difference in the possible protective antibodies produced during vaccination. Continuing forward, this finding will help us elucidate bacterial OMPs that are the targets of protective antibodies.