Study On New Complex Polysaccharide Adjuvant Of FMDV Vaccine

Adjuvant is an important active ingredient in vaccinum,which can improve the immunogenicity of antigen,promote immunity from different ways,reduce the use of antigen and achieve the desired effect of immunoprotection at the same time.At present,the most frequently used vaccine adjuvants for livestock are oil adjuvant,aluminum salt adjuvant,etc and most of them have toxicity,single action way and non metabolism,which causes the side reaction of vaccinated animals and failure to achieve the desired effect.This study investigates the natural plant polysaccharide as adjuvant in order to seek a natural immune adjuvant with low toxicity and high efficiency and obtain natural and well effective polysaccharide formula with no side effect as vaccine adjuvant for livestock.Carries out purification and physicochemical properties analysis of the seven polysaccharide,namely,Astragalus polysaccharide(APS),Ginseng polysaccharide(GPS),Mulberry polysaccharide(MPS),Lentinan(LNT),Hibiscus polysaccharide(HPS),LBPS,Yunzhi polysaccharide(YPS).APS,GPS,LBPS and YPS with better effects were screened after purification,physical and chemical property detection,safety evaluation,immunoregulation dose determination and immunomodulation comparison.The ratio of the four polysaccharides was optimized and the Complex polysaccharides(CPS)was compounded to explore the feasibility of CPS as an adjuvant.The polysaccharide was purified through enzymolysis,extract,freeze-drying and other technologies and studies the immunomodulatory effect and the best immunizing dose of various polysaccharides of the Balb/c mice model,evaluated for their security,the determination results are respectively APS 94.1 %,GPS83.5 %,MPS 91.4%,HPS88.9%,LBPS78.5 %,YPS 81.1 %,LNT 92.6 %.The best immunizing doses are respectively APS 250 μg /mL,GPS 375 μg /mL,MPS 750 μg /mL,HPS 125 μg/mL,LBPS 125 μg/mL,YPS 500μg /mL and LNT 500 μg /mL.Only HPS containing momordin exceeds 2.5 mg/Kg in injected dose,which has the toxicity to the cell.HPS is studied as a contrast.The result shows that the rest six polysaccharides had no toxic side-effect.It studies the immunomodulatory effects of various polysaccharides on swine O type foot-and-mouth disease OS/99 strain inactivation purification antigen among the mice model.It evaluates the humoral immunity with specific antibody level and cellular immunity with secernent IFN-γ and IL-12 cell factor.The result shows that the antibody level containing LBPS,GPS,LNT,APS,YPS after secondary immunization of same dose is higher than that of MPS and LNT group,which has better effect and significant differences(p<0.05)compared with antigen diluents negative.According to the cell factor model in mice serum,APS can promote both humoral and cellular immunity,LBPS and YPS can promote cellular immunity,while GPS,HPS and MPS can promote humoral immunity.The animal experiment(swine model)is selected for compound polysaccharide formulation after the exclusion of MPS,LNT and HPS with strong cytotoxicity that have week immunomodulatory effect.The medium dose group is determined as the best formula after the comparison of low,middle and high level complex polysaccharide.The complex polysaccharides(CPS)is obtained through the 4 kinds of polysaccharides component contents in single factor experiment optimized formula.Total polysaccharide content of CPS is 32.5 g/L,including APS 7.5 g/L,GPS 11.25 g/L,LBPS 3.75 g/L,YPS 10 g/L.0.5% non-ionic surfactant Tween 80 was added to the formula to promote the dissolution and 0.05 % carbomer 971 P is added to increase the adjuvant viscosity.This complex polysaccharide adjuvant can delay absorption and promote the permanent suspension of insoluble additives,thus increasing the stability of the vaccine.CPS is used as the inactivated vaccine of immunity adjuvant preparation FMD and the contrast immune animal by using ISA206 and ISA50 V.The test result shows that CPS can promote not only the humoral immunity but also cellular immunity.CPS is used as the immune potentiator diluted antigen.The ISA206 and ISA50 V emulsification vaccine and the animal immunity result shows that CPS can make up for the defects of oil adjuvant and promote cell immunity reaction ability as as immune potentiator.CPS is certain promotion value as immunologic adjuvant and immune potentiator.