Identification And Characterization Of Heme Binding Protein Of Haemophilus Parasuis And Its Roles In Pathogenesis

In recent years, Haemophilus parasuis disease which trends to explosive and high death rate 50%, has become the world’s most important bacterial disease and caused tremendous economic losses to the pig industry.In order to study the function of HbpA protein in Haemophilus parasuis (HPS) and its role in pathogenicity, to explain virulence characteristics and the pathogenesis in a new perspective, this study explored the biological function of HbpA protein using Immunoproteomics technology, imploying the theoretical basis of functional genomics with newly discovered HbpA immunogenic protein as an entry point. The results were as follows:1. Got a periplasmic protein HbpA which had immunogenic using the technology of proteomics and.2. Got a recombinant plasmid pET28a-HbpA and induced expression of soluble protein, which had a size of 59.4kD, PI= 7.06 using the technology of recombinant DNA.3. Protein HbpA could react with monoclonal antibody of HbpA from murine which proved specificity using the technology of.4. Protein HbpA could bind Heme in vitro environment with the methods of Heme-agarose binding, the molecular weight of HbpA-Heme complex increased with increasing concentrations of Heme within a certain range (0mM-4mM); the complex would not increase, but remained at a constant value when Heme reached a certain limit (4mM).5. Complex of protein HbpA from wild strains and Heme was mainly presented in the cell membrane, inner membrane and nucleus using the technology of IEM.6. HPS indeed expressed protein HbpA in lungs of pigs with Immunohistochemistry.7. Proved Fe2+was an important element in the living and breeding of HPS by measuring its growth curve.8. Antibodies of HbpA could kill almost half of HPS using the technology of sterilization in vitro with antibodies.9. Expression of protein HbpA was twice when lack of Fe2+than in normal circumstances by the technology of RT-PCR.This study clarified the function of protein HbpA in survival, reproduction and pathogenic mechanisms of HPS from the level of molecular and explained the virulence characteristics and pathogenesis of infection of HPS in a new perspective, which had a certain theoretical and practical significance in the study of effective vaccines and drug blockers.