Preliminary Study On Outer Membrane Proteins Proflies And Immunogenicity Of Haemophilus Parasuis

Haemophilus parasuis is a commensal organism colonized on the upper respiratory tract of pigs, which can cause Glasser's disease characterized by polyserositis, polyarthritis and meningitis with high mobidity and mortality in a special condition. The disease has made a huge economic losses to pig industry all over the world. It is very important in theory and practice for exploring the pathogenic mechanism of H. parasuis and for theoretical basis of immunoprophylaxis of Glasser's disease to research the epidemiological characteristics, find out the diversity of the outer membrane protein (OMP) profiles, and reveal the relationship between the virulence factor and isolates.In the paper,82 strains isolated from Jiangxi province, Guangdong province, and Shanghai were analysed by SDS-PAGE to compare the diversity of OMP profiles among the strains of H. parasuis in diffent clinical backgrounds and explore their association with the virulence of isolates. OMP fingerprinting of every isolate was scanned by softwares TotalLab100 and Bandscan5.0, after then cluster analysis was proceeded by a special software SPSS 16.0. Antisera were prepared for 5 field isolates with highly virulence, with which western blot was performed to find out the immunogenic components and common determinants of OMP and whole-cell proteins. The main results are as follows:1. OMP was successfully extracted from H. parasuis by Sarkosyl method.2.The OMPs of 82 strains of H.parasuis were analysed by SDS-PAGE. Comprehensive analysis including SDS-PAGE pattern of OMP, cluster analysis and immunological analysis showed that H.parasuis isolates were divided into 2 major PAGE types. PAGE type II characterized by the major proteins with molecular weights varying from between 36 and 40KD included about 34% strains from the diseased pigs and 9% strains from the healthy pigs. But PAGE type I strains lacked the particular protein. It is suggested that the 36-40KD OMP is likely associated with virulence.3. The 5 hyperimmune antisera prepared for 5 strains of H. parasuis in different sources could react remarkedly to OMP of the homologous isolates, of which the responsive proteins were 28～31 KD and 38-40KD in molecular weights. These antisera could also react obviously to various components of whole-cell proteins.4. Five antisera showed a good effect in cross-immune against strains of different clinical origins. Both OMP and whole-cell proteins of the isolates from the diseased pigs showed strong immunogenicity, but OMP of isolates from the healthy pigs indicated weaker immunogenicity than whole-cell proteins. In addition, OMP of isolates from diseased pigs are stronger than those in healthy pigs. So it is deduced that the cross-react among H.parasuis isolates could be probably associated with the clinical background.5. Most strains of H.parasuis shared common immunogens on OMP with molecular weights between 37 to 40KD and 27 to 31KD which have strong immunogenicity. These proteins would be considered as for candidate vaccine.