Selection Of CpG From Microbe As Vaccine Adjuvant

CpG-DNA is DNA sequence that contains unmethylated motifs and have immuno- stimulatory effect.It includes synthetical oligodeoxynucleotides containing unmethy- lated CpG motifs and genome DNA of low being in nature. Most studies proved that CpG-DNA is able to stimulate immune cells to secrete many cytokines .adjust some factors, induce activity of immune system and produce special immune responses.In this study ,we composed thirty two CpG sequences according to the speciality of CpG -DNA and chose four sequences that have significant effect and safety by immune trial in animals. Following is the works of our study.Twenty seven CpG-DNA sequences containing no endotoxin were found in four bacterium and synthesized in BGI Life Tech Co.,Ltd. In study of antigen gene of Fuso-bacterium necrophorum.five sequences containing CpG-rich motifs were found.Otherwise,it was found that D.nodosus serotype C pili gene has CpG-rich motifs. Plasmid were separated from CP6 and digested by ECOR1 for sequencing of CpG- DNA.Sterile blood samples were collected from sheep and mice and separated lympho-id cells.Fore sequences that have stimulative effect to cell reproduction were chose by lymphoid cells reproduction trial. Safety trial in animal proved that it are safe.Vaccine containing FCA ,vaccine containing CpG and Al(HO)₃,vaccine containing CpG and vaccine containing Al(H0)3 were prepared respectively by antigens of Fuso- bacterium necrophorum and recombined pili protein antigen of D.nodosus.Mice were injected with these vaccines.The results showed that the vaccine containing CpG have short immune cycle ,but vaccine containing CpG and Al(HO)₃ have similar immune effect with vaccine containing FCA. Otherwise,the fact that CpG-DNA gained fromplasmid and whole plasmid as adjuvant have same effect suggested that CpG plasmid produced from CpG plasmid strains of bacterium may be immediately used in vaccine production.