Pathological Observation Of Ovine Echinococcosis And Research On Expression Of Recombinant EG95Antigen

Echinococcosis, which is also called cystic echinococcosis, is a severe zoonosiscaused by the larval stage of Echinococcus granulosus parasite. It threatens publichealth and causes economical loss in livestocks. The disease is mainly prevalent inagricultural and pastoral areas, and its incidence is very high in China particularly in thenorthwestern and western provinces or autonomous regions such as Gansu, Xinjiang, Ningxia,Inner Mongolia, Qinghai, Sichuan, Shanxi and Tibet with direct economic losses of over3billion Yuan annually. The main control strategy of the disease is to take comprehensiveprevention measures. However, these measures have not obtained the expected effect due tovarious reasons. The immune preventive method with vaccines will be one of the ideal waysto control the disease. Recombinant antigen vaccines for this disease have great applicationvalue and their development has made a great progress with the growth of new technologiesof modern molecular biology, biological chemistry and immunology. Many research resultsshow that the EG95protein is one of the most effective antigens found to date, and the studyof EG95recombinant antigen vaccine is becoming the highlight of this research field.Livers and lungs with hydatid cysts were collected, and paraffin sections were madefollowed by section staining with hematoxylin-eosinand. Pathological observations of thesections indicate that the histological structure of the cysts had classic characteristics ofparasites disease. The inside of the cyst is a structure like red shelf which mainly formed withepithelioid macrophages and a small amount of multinucleated giant cells, lymphocytes andeosnophils. The damage to the liver of the cyst inculds pressure atrophy, cirrhosis andanaphylaxis inflammation, and the harm to lung manifested as interstitial pneumonitis andanaphylaxis inflammation.Protoscolexes were used for extraction of genomic DNA and ND1gene was amplifiedwith PCR method and then sequenced. The ND1secquence was blasted in GenBank, and theresult demonstrated that the ND1gene was the same as that in G1genotype of E. granulosus suggesting sequencing analysis of ND1should define genotypes of E. granulosus.Predication analyses of characters of EG95protein with a series of softwares are helpfulfor the identification of its signal peptide and hydrophobic regions. Recombinant expressionsystems using different expression vectors with EG95gene and its derived EG95genefragments were constructed and expressed in E. coli Rosetta (DE3). The target proteinsincluding inclusion body and soluble protein were isolated with SDS-PAGE, and thentransfered to nitrocellulose membrane followed by analysis of its immunogenicity usingWestern-blot. The result showed that EG95protein had good immunogenicity. This study haslaid a solid foundation for the development and production of echinococcosis vaccines.