Effect Of Different Immune Process Of CSF And PRRS Vaccine On Immune Efficacy

Classical swine fever (CSF) is an acute viral infection of pigs that causes major economic losses especially in countries with dense populations of domestic pigs. Porcine reproductive and respiratory syndrome (PRRS) is one of the most important pig diseases worldwide with a huge economic impact, estimated in the USA alone to exceed $600 million annually.Pigs will die because of the completely lost of immunity and secondary infection of other diseases after infected with this two diseases.CSF and PRRS both belong to immunosuppression diseases although they have the different nosogenesis. Immunosuppression diseases are one of the most important factors that cause the immunity failure of each hoggeries.So a good control to the occurrence of immunosuppression diseases actually is the urgent affairs during the immune prevention and control.However, a unitive and effective immune procedure has not been formed so far.Therefore,developing the study on a unitive and effective immune procedure is a task which brooks no delay.36 weaned piglets were randomly divided into 3 groups (A、B、C) with 2 replicates.6 weaned piglets as control group. Group A first immunize the piglets against CSF and 7 days later against PRRS.Group B is in reverse.Group C immunize the piglets against CSF and PRRS at different locations at the same time. Blood samples were taken from cranial vena cava once every 9 days during 70 days after immunization for analyzing blood routine examination, ratio of feed to gain,level of antibody production in humoral immunity,ability of T lymphocyte proliferation and level of IFN-γ production in cellular immunity. The results as follows:①The blood index results showed that the average number of white blood cells and lymphocytes in the three groups reached the peak at about 30th days.Group A and C were significantly higher than Group B (p<0.01).There were no significant differences in other indicators among the three groups (p>0.05). ②The ratio of feed to gain in Group A was the best, then Group C and Group B the poorest.③The ELISA kit test results showed that the average blocking rate of specific antibody of CSF in Group A reached the peak at about 70th days and significantly higher than Group B (p<0.01) and Group C (p<0.01), Group B was the poorest (p<0.01). The S/P value of specific antibody of PRRS in three groups all showed an increasing trend and reached the peak at about 40th days.There was significant difference before and after the immune in three groups (p<0.01),but the difference among three groups is non-significant (p>0.05).④Ability of T lymphocyte proliferation results showed that the average stimulation index(SI) in Group A reached the peak at about 40th days and significantly higher than Group B(p<0.01)and Group C(p<0.01), Group B was the poorest (p<0.01).⑤Level of IFN-y production results showed that the average concentration of IFN-γ in Group A reached the peak at about 40th days and significantly higher than Group B (p<0.01),the difference is non-significantcompared with Group C (p>0.05)Stated thus,the results of blood routine examination, ratio of feed to gain,level of humoral immunity and cellular immunity all indicated that first immunize the piglets against CSF and 7 days later against PRRS showed a better immune effect.This conclusion will provide theoretical basis for formulating a reasonable and effective immune procedure of CSF and PRRS in the future.