The Study Of Immune Efficacy On Co-immunization Of Coniaiercial FMDV Vaccines And CSFV Vaccines In BALB/c Mice

Foot-and-mouth disease （FMD）is an acute，violent and highly contagious zoonotic disease of thecloven-hoofed animals, which is caused by the foot-and-mouth disease virus （FMDV）.Classical swinefever （CSF） is a highly contagious viral disease，which is caused by classical swine fever virus （CSFV）.They were both enlisted as members on the List A of contagious diseases by OIE. Up to now, vaccinesare the most effective methods to prevent these two diseases. However, the FMD vaccines and CSFvaccines are injected respectively at different time, which results in longer immunization period，morecases of stress reaction and higher cost.To detect the immune efficacy of simultaneous vaccination of two commercial vaccines againstfoot-and-mouth disease （FMD） and classical swine fever （CSF） in a mouse model, the variation ofimmune responses after immunity was studied. The BALB/c mice were divided into four groups:⑴FM D V vaccine alone;⑵CSFV vaccine alone;⑶FM D V vaccine+CSFV vaccine;⑷PBS. Theantibody titers, IFN-γ and IL-4in the serum were detected on the day7after the second vaccination.The lymphocyte proliferation test and CD3⁺CD4⁺/CD3⁺CD8⁺T cells detection was performed usingthe splenic lymphocytes isolated on day7after the second vaccination. The antibody titer against FMDin the co-immune group was lower than that of the FMD group, but the antibody titer against CSF in theco-immune group was far higher than that of the CSF group. The level of INF-γ of the co-immunegroup was higher than that of the FMD group, but lower than that of the CSF group. Through thedetection of the proliferation of spleen lymphocytes of mice and the flow cytometry analysis, we foundthat, co-immunization had an important influence on the immune response when the splenic lymphocytemet the same specific antigen again, and it also played a vital role in the differentiations and functionsof T cell subsets. Collectively, these studies suggest that the effective humoral immunity responses wereinduced by co-immunization of FMD and CSF vaccines; however, the cellular immune responses toFMDV were inhibited by co-immunization.Adjuvants are substances that can improve the immunogenecity of antigens （immnogens） afterImmunization. By using certain adjuvants, the immune responses can be oriented to either humeral orcellular direction for establishing protectiv eimmunity.The intact140S FMDV O strain antigens wereobtained through the chemical inactivation method. Then the140S antigens were concentrated andpurified by sucrose density gradient centrifugation. In order to compare the immune efficacy of differentadjuvants, we chose Al （OH）₃, ISA206and Poly （I: C） formulated with140S FMDV antigens. Balb/cmice were divided into different groups（⑴FMDV+Al（OH）₃（F+A）；⑵FMDV+Poly（I:C）（F+P）；⑶FMDV+Al（OH）₃+Poly（I:C）（F+A+P）；⑷FMDV+ISA206（F+206）；⑸PBS（PBS））and injectedintramuscularly with specific vaccines. The antibody titers induced by ISA206and Al （OH）3+Poly （I:C） were higher than that induced by Al （OH）₃.Through the stimulation by specific antigens in vitro, theconcentration of IFN-γ and IL-4were higher in the ISA206group, which indicated that ISA206mayhave the potential to enhance the humoral and cellular response. In the splenic lymphocytesproliferation test, the ability to induce the lymphocytes proliferation was stronger in the ISA206group.Our findings suggested that ISA206is the preferential adjuvant which could better formulate withinactivated FMDV antigens.however，when immunized with both Al（OH）₃and Poly（I:C），the immune efficacy of the antigen was improved a lot.