Submitted to: Biochemistry and Molecular Biology Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/6/2000
Publication Date: N/A
Technical Abstract: Haemophilus parasuis is a reemerging pathogen of swine raised in high- health status production facilities. In the absence of colostral transfer of antibodies to the piglets, the presentation of the pathogen to non- immune animals, and stress due to weaning and/or a co-infection with other bacterial or viral pathogens results in a rapid dissemination of the organism resulting in pleuritis, meningitis, polyserositis, septicemia and death. Efficacious vaccines are not commercially available and autogenous whole-cell bacterin vaccines are not always effective due to the rapid phenotypic changes of the pathogen. Very little is known about the immunoreactive protein antigens of H. parasuis for development of a non- infectious vaccine. In this study we identified a major immunogenic protein present in culture lysates prepared from a virulent (serovar 5) and a somewhat less virulent serovar (serovar 4) of H. parasuis. Peptide fragments prepared from a Lys-C digest of the blotted protein was purified by C-18 HPLC, and sequenced. A Blast search of the peptide sequences revealed that they were homologous to the H. influenzae elongation factor Tu. Purification of native EFTU from culture lysates by differential ammonium sulfate precipitation, ion exchange chromatography and gel filtration by HPLC, showed a heterogeneous group of immunoreactive isoforms of EFTU by SDS-PAGE and Western blotting. Even though EFTU is a cytoplasmic protein, it is interesting to note that this protein is a major immunoreactive protein. Reports that many cells are "leaky" with respect to EFTU would explain its immunoreactivity.