The Screening Of Chicken CpG ODNs And Their Immunoenhancements On ALY Subunit Vaccines

CpG oligodexynucleotides (CpG ODNs) are a class of DNA sequences that contain unmethylated CpG,which can activates mammal’s Toll-like receptor (TLR)9and chicken’s TLR21and promote the proliferation of lymphocyte, induce the bioactivation of monocytes macrophages and dendritic cells and the expressin of variety cytokines, and can also be used as adjuvants of vaccines in clinical medical science. Some researches show that the bioactivities of CpG ODNs are different with the changes of chemical structures and animal species. Little was known about the effects of CpG ODNs on chicken’s lymphocytes and the immunoenhancement of them on ALV subunit vaccines. This study designed four kinds of CpG ODNs with different bp length named CpG-Ⅰ、CpG-Ⅱ、CpG-Ⅲ、CpG-Ⅳ in proper order, three kinds of CpG ODNs with different phosphorothioate modification named CpG-S1、 CpG-S2、CpG-S3. The stimulated proliferation ability of them on SPF chicken’s blood and spleen’s lymphocytes were screened using MTT methods in vitro. The immunoenhancement of them on vaccines were analyzed using inoculated chickens’experiments with them combining with ALV subunit vaccines and AⅣ-H5unactivated vaccines. The serum antibody of the vaccinated chickens and the expression of chicken TLR21were detected, respectively. The results show that all the CpG ODNs can activate the proferation ability of chicken’s blood and spleed’s lymphocytes, and CpG-Ⅱ and the CpG ODNs with partly phosphorothioate modification has the best bioactivities on the lymphocytes proliferation. The CpG ODNs with different bp lengths can all increase the serum antibody titers and the positive ratio of ALV subunit vaccines, but CpG-Ⅳ can improve the higher antibody titers and the antibody positive ratios than the others; The different phosphorothioate modification of CpG ODNs can effect their bioactivies on serum antibody, but CpG-S3with full phosphorothioate modification are better than the others. CpG ODNs with different bp lengths can also enhancethe serum antibody titer of AIV-H9vaccines, and different phosphorothioate modification can effect the enhancement of CpG ODNs. The chickens vaccinated using CpG ODNs with different bp lengths and different phosphorothioate modification could express more TLR21mRNA than control chickens. After vaccinated using CpG-Ⅳ with full phosphorothioate modification, combining with ALV-A gp85subunit vaccine, the hen produce more serum antibody and maternal antibody. It can be concluded that the chemical structure and phosphorothioate modification of CpG ODNs can effect their bioactivities on chickens and some of them can more enhance ALV subunit vaccine’s immunogenicities.