鸡IL-2、IL-18、IFN-γ cDNA和CpG DNA在减毒沙门菌运送H5亚型禽流感DNA疫苗中的佐剂作用

The adjuvant effects of chicken IL-2, IL-18, IFN-γ and CpG DNA on HA DNA vaccines against H5 sub-type of avian influenza virus delivered by attenuated Salmonella

目的探讨鸡IL-2、IL-18、IFN-γcDNA和CpG DNA在减毒沙门菌运送H5亚型禽流感DNA疫苗中的佐剂作用。方法将携带禽流感病毒(AIV)DNA疫苗的重组沙门菌SL7207(pVAX1-HA- IL2)、SL7207(pVAX1-HA-IL18)、SL7207(pVAX1-HA-IFN-γ)、SL7207(pVAX1-HA-CpG)、SL7207(pVAX1-HA)和SL7207(pVAX1)经口服和滴鼻途径首免1日龄商品代伊莎褐蛋鸡,测定免疫鸡的体液和黏膜免疫应答水平,并进行攻毒保护试验。结果二免后3周,SL7207(pVAX1-HA-CpG)、SL7207(pVAX1-HA- IFN-γ)免疫组以及SL7207(pVAX1-HA)和SL7207(pVAX1-IFN-γ)联合免疫组鸡产生了较高水平的特异性黏膜免疫应答(P<0.05),但重组菌免疫鸡血清中抗AIV HI抗体水平与空载体组相比差异无统计学意义。SL7207(pVAX1-HA-CpG)、SL7207(pVAX1-HA-IFN-γ)的免疫保护指数显著高于阴性对照组。结论初步观察佐剂效应依次为:CpG>IFN-γ>IL-18,IL-2未表现出佐剂效应。

Objective To evaluate the adjuvant effects of chicken IL-2, IL-18, IFN-γ and specific CpG DNA on HA DNA vaccines against H5 subtype of avian influenza virus delivered by attenuated Salmonella. Methods recombinant expression plasmids and pVAX1 were transformed by electroporation into an attenuated Salmonella typhimurium strain SL7207, and the recombinant bacteria were screened and designated as SL7207 （pVAX1-HA-IL2）, SL7207 （pVAX1-HA-IL18）, SL7207 （pVAX1-HA-IFN-T）, SL7207 （pVAX1-HA-CpG）, SL7207 （pVAX1-HA）and SL7207 （pVAX1） respectively. One-day-old commercial ISA brown chickens were immunized oraUy and inky twice with the different recombinant Salmonella at dosage of 5 × 10^9 CFU at a twoweek interval. Results The significant increased of IgA titers were found in immunized groups of SL7207 （pVAX1-HA-CpG）, SL7207 （pVAX1-HA-IFN-T） and SL7207 （pVAX1-HA）＋ SL7207 （pVAXI-IFN-γ） group. The fliers of serum specific antibodies in positive control group were significantly higher than those of other groups three weeks at second PI （ P 〈 0.05）. After intranasally and orally challenged with virulent strain of H5 subtype of avain influenza virus, the protective index of SL7207 （ pVAX1-HA-CpG）, SL7207 （pVAX1-HA-IFN-γ） and positive control groups were significantly higher than those of negative control groups （ P 〈 0.01 ）. Conclusion The adjuvant effects of CpG DNA are better than those of chicken IFN-γ, IL-18, IL-2 was not effective.