【摘要】 为研究双顺反子DNA疫苗对禽流感病毒(AIV)的保护作用,将H5和H7亚型AIV的HA基因克隆到同一表达载体上,构建了双顺反子HA基因表达质粒pCI-H5HA-H7HA。以此质粒肌注免疫4周龄SPF鸡,首次免疫后3周加强免疫,同时设pCI-H5HA和pCI-H7HA联合免疫组及空白对照组,每周采血用微量血凝抑制法检测HI抗体。加强免疫后3周分别以100LD50的高致病力禽流感病毒(HPAIV)A/Goose/Guangdong/1/96(H5N1)和A/FPV/Rostock/34(H7N1)进行致死性攻击。结果显示各免疫组均可刺激鸡体产生H5、H7特异性抗体,pCI-H5HA-H7HA诱导产生的抗体对H5N1和H7N1的攻毒保护分别为50%和10%,而pCI-H5HA和pCI-H7HA联合免疫的攻毒保护均为70%。表明双顺反子质粒可诱导鸡产生较好或一定的保护,但免疫效果不够理想,推测与DNA的摄取及其体内表达有关,可望通过调整DNA疫苗的多种因素提高免疫效果。更多还原

【Abstract】 The protective efficacy of a plasmid DNA that contains two AIV HA genes was evaluated in SPF chickens.Two AIV HA genes of H5 and H7 subtype were cloned into the same vector,thus a dou-blegene vector-pCI-H5HA-H7HA had been constructed successfully.And this plasmid was used to immu-nize 4-week age SPF chickens by intramuscular injection.For comparison,another group of SPF chick-ens were vaccinated with pCI-H5HA and pCI-H7HA jointly.The Haemagglutinin inhibition(HI) titer induced by DNA vaccine were tested weekly for 6 weeks and the protection ratio were calculated.The SPF chick-ens were challenged with H5N1 or H7N1 isolate of HPAIV at the sixth week after the immunization.And the result showed,50 % and 10 % protection rate against H5N1 and H7N1 were obtained prospectively from pCI-H5HA-H7HA vaccinated groups,while 70 % of protection rate were obtained from the groups immunized with pCI-H5HA and pCI-H7HA jointly.The study suggested the possibility that the dou-ble-gene plasmid can induce protection more or less,but the titer is yet unsatisfactory,inferring that the ingestion of DNA and its expressionlevel may play an importantrole.In orderto improve the protec-tive efficacy,the further study on various influencing factor is still needed.更多还原