The PLGA Microballoons Coated Technology Study Of 3-1E Recombinant Of Eimeria AcervuLina

The prevalence rates of coccidiosis caused by E.acervulina in the intensive chicken farm is the highest. E.acervulina caused serious economic losses in poultry industry which in the intestinum, a medium toxicity. Coccidiosis control rely mainly on drugs and live vaccines, since drug resistance and drug residues and other issues, live vaccine but also high cost, cumbersome operation, immunization requirements of high and other defect, prevention and control of coccidiosis serious in need of new ways. A significant advantage of DNA vaccine is stimulated the body produces a wide range of cellular immune response and long-lasting immune memory, However, administration of naked plasmid DNA vaccine approach is not convenient enough, tissue irritation and high cost. Naked plasmid DNA vaccine in the practical application of oral immunization due to gastric acid, pepsin, etc. on the impact of cracking antigen, leading to the inactivation of the plasmid vaccine, produced a low immunosuppressive effects, sufficient immunity can often be done by increased the immune dose. In this experiment, E.acervulina recombinant plasmid pcDNA3.1-3-1E is coated by PLGA hydrophobic material as the research object, microballoons was made and use this microballoons in animal experiments, laid the foundation for the development of efficient and safe vaccine against coccidiosis new dosage forms and oral immunization.The PLGA was used as a carrier and pcDNA3.1-3-1E was used as model drugs, the pcDNA 3-3-1E PLGA microballoons was preparation via W/O/W emulsification technique. The form, pa- rticle diameter, plasmid DNA encapsulation efficiency, drug loadings and rele- ase behavior of m- icrospheres were evaluated and, it was indicated that plasmid DNA can be parceled by PLGA suc- cessfully. The envelope rate and drug loading capacity was 82.7%,1.89%,respectively. About 80% particle diameter is of less than 12μm. In the ex- periment model, the cumulative-release ability of stomach intestine fluid was pH 3.0>pH 7.4 in turn, and microballoons cumulative release duri- ng 30d was 81.3%, suggested micr- ospheres have slow-releasing effect. Naked plasmid and mic- rosphere plasmid super spir- al proportion was not obvious, and suggested that super spiral plasm- id did not degradation after coated.In this study, we took samples of 1d,10d and 30d after treated with microballoons oral immu- nization of pcDNA3-3-1E PLGA and intramuscular immunization of recombinant plasmid pcDNA3-3-1E and we later discussed their distribution in various tissues.3-1E gene can be detec- ted in both oral immunization group and intramuscular immunization group after immunization 1d, 10d. 30days after immunization, 3-1E gene was still detected in tissues of oral immunization group, while in the intramuscular group the 3-1E gene was only detected at the injection site, sho- wed that the oral pcDNA3-3-1E PLGA microballoons can be absorbed in the body at least 30d. After pcDNA3-3-1E PLGA microballoons immunization, in different time the chicken peripheral blood lymphocyte transformation level and IgG was significantly increased, indicated that oral ad- ministration of pcDNA3-3-1E PLGA microballoons can effectively improve the level of cellular immunity and humoral immunity.In this test, pcDNA3-3-1E PLGA microballoons is vaccinated by oral immune, and healthy controls, Naked plasmid+ intramuscular immunization group and oral group were set. The initial immunization and booster immunization were carried out at 7d and 14d respectively.Poisoning the chicken with 5×10~4 E.acervulina BD one week later . The immunization effect of recombinant plasmid pcDNA3-3-1E was evaluated via increased weight, pathological changes, oocyst production and ACI, etc. The result showed that oral pcDNA3-3-1E PLGA microballoons chicken oocyst production decreased 88.72%, intestinal pathological changes score reduced 63.96%, relative weight gain and ACI were 96.89% and 165.19 separately after administrated with E.acervulina, compared with control。The results showed that, PLGA can effectively protect the pcDNA3-3-1E in the gastrointestinal environment from destruction, to prevent vaccine inactivation and degradation, and improve the transport efficiency of DNA vaccines to enhance immune response. PLGA as a carrier in oral vaccines become a major direction.