Study On The Adjuvant Effect Of IL-2 And PUC18-CpG

Currently,the widely used vaccine against duck tembusu virus(DTMUV)disease is inactivated vaccine which,however,facing the limits of large inoculation dose,short immunization period and incomplete effectiveness.Access to efficient adjuvants aiding for DTMUV inactivated vaccine seems to be of critical importance.Interleukin-2(IL-2)was reported to induce a persistent expansion of effector T cells and could be a promising molecular adjuvant for many kinds of vaccines.In this study,the efficacy of duck IL-2(dIL-2)as an adjuvant for a DTMUV inactivated vaccine was evaluated.42-day old ducks were divided into four groups and intramuscularly administered the vaccines coupled with or without dIL-2,respectively.Antibody titers and cytokine responses were used to assess humoral and cellular immune responses in serum of inoculated ducks,respectively;virus isolation and RT-PCR method were used in immunity protective test.The elevations of HI antibody titers,PI,and cytokines responses,and higher protection rate after virus challenge revealed co-inoculated dIL-2 enhancedthe immune effect of inactivated vaccine against DTMUV.Furthermore,while ensuring the above immune effect,IL-2 could reduce the inoculation dosage.Our results showed that dIL-2 exerted an enhanced effect on the vaccine while reducing the dose of inoculated antigen highlighting high adjuvanticity of IL-2.The immune effects of commercialized pUC18-CpG on inactivated antigen of H9 subtype avian influenza virus(AIV-H9)were investigated by intramuscular injecting of SPF chickens at the age of 1,7 and 21 days.The results showed that the HI antibody titers in the pUC18-CpG+H9 groups were significantly higher than that in the non-additive groups.HI peak antibody were log2 titers higher and HI antibodies are also rising faster than that in the non-additive groups.Besides,in pUC18-CpG+H9 groups,the immune effect at 21 day-old SPF chicken group was significantly better than that in 1 and 7 day-old SPF chicken group.The results showed that HI antibody increased faster,the peak titer was higher,and the dispersion was smaller.Our results indicated pUC18-CpG could significantly enhance the specific humoral immune response to AIV-H9,and could be used as an effective immunoenhancer.