| Haemophilus parasuis is classified as second-class animal disease in China.In recent years,there have been more and more reports on the serious losses caused by the disease in the pig industry at home and abroad.Antibiotics are currently the main method for the prevention and treatment of Haemophilus parasuis,but with the expansion of antibiotic resistance spectrum of Haemophilus parasuis and the increase of drug resistance,antibiotic control has not achieved the best results.Therefore,More scholars have begun to work on the development of vaccines.In this study,three types of inactivated vaccines for the prevention and control of Haemophilus parasuis were prepared by using serotypes 4,5,and 13 of Liaoning Province.In accordance with the traditional inactivated vaccine configuration method,Explore new adjuvants as a substitute for traditional adjuvants.The results of the immuno-protective evaluation using KM mice provided reliable data for the preparation of trivalent inactivated vaccine against Haemophilus parasuis.Provide reference for the clinical prevention and control of Haemophilus parasuis,trivalent inactivated vaccine has great application value and practical significance for the development of pig industry in Liaoning Province and even the whole country.In the first experiment,New compound adjuvant was used instead of traditional adjuvant and trivalent inactivated vaccines were prepared in accordance with conventional methods and three isolated strains of Haemophilus parasuis serotypes 4,5,and 13 to establish two different combinations.The bacterial counts were 2.0×10~9 CFU and 4.0×10~9 CFU,respectively,and their physicochemical properties were evaluated and their safety tested.The results showed that:1)In the assessment of physicochemical properties,the prepared inactivated vaccine was light yellow,opaque,uniform in system,and free of foreign matter;the vaccine system was O/W type;the viscosity was 6 s/0.4 mL.The culture medium was determined to grow aseptically;the trivalent inactivated vaccine was stored at 4°C for a long period of time and was still clarified after six months,and no demulsification or eclosion occurred.2)The safety test showed that after immunization,the KM mice had a good mental state and normal feeding.No bulging was seen at the injection site,and there was no redness and bleeding on the back skin.Experiment 2 was performed twice in the immunoprotection test,and blood was collected at 7d,14d,21d,28d,and 35d after immunization.The T lymphocyte proliferation rate assay,indirect hemagglutination test,and Haemophilus parasuis antibody were used.(HPS Ab)Enzyme-linked immunosorbent assay(ELISA)was used to detect the dynamic proliferation of T lymphocytes in peripheral blood and antibody titers and antibody concentrations in different KM-immunized mice,then challenged them after 35 days.The effectiveness of trivalent inactivated vaccines.The results showed that:1)the proliferation rate of T lymphocytes in peripheral blood of mice was increased in both group 1 and group 2 of the prepared trivalent inactivated vaccine.The antibody levels of the two groups were slightly better than those of the commercial vaccine group and the white oil group.2)trivalent inactivated vaccine 1 set of type 4,5,and 13 strains against poison protection are all 50%,trivalent inactivated vaccine immune type two groups of 4,5,and 13 strains,which were 75%,immune protection effect is slightly better than commodity seedlings in the control group.To sum up,the immune protection effect of the HPS trivalent inactivated vaccine preliminarily developed in this study has a good immune protection capability for the strains of HPS 4,5 and 13. |
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