【摘要】 为研究ＤＮＡ疫苗对禽流感病毒（ＡＩＶ）的保护作用，将禽流感病毒Ａ／Ａｆｒｉ．Ｓｔａｒ．／Ｅｎｇ－Ｑ／９８３／７９（Ｈ７Ｎ１）株血凝素基因ｃＤＮＡ置于ＳＶ４０启动子和增强子下游，构建了ＨＡ基因表达质粒ｐＳＶＨ７。以此质粒肌注免疫３周龄ＳＰＦ鸡，免疫后第４周用１００倍最小鸡胚感染量的ＨＡ基因同源病毒人工感染，１周后用棉拭子取样进行泄殖腔病毒分离。免疫后每周及攻毒后第１、２周采血，微量血凝抑制法检测抗体。病毒分离阴性结果：１００μｇ／只组为６／６，１０μｇ／只组为４／６，１μｇ／只组为５／８，空白对照组为０／６。攻毒后１周相对应的４组血凝抑制价依次为：１∶３２～６４，１∶１６～６４，１∶４～６４，１∶４～１６，表明所构建的Ｈ７亚型ＨＡ基因表达质粒可诱导鸡产生有效的免疫保护反应。更多还原

【Abstract】 It has been demonstrated that direct DNA inoculation can elicit protective immune response in chicken against avian influenza virus (AIV). In this study, we constructed an H7 haemagglutinin (HA) expressing plasmid pSVH7 by inserting the HA cDNA from AIV A/Afri. Star/Eng Q/983/79(H7N1) under SV40 promoter and enhancer. 3 week old chickens were vaccinated with pSVH7 at 100μg per bird in Group 1 (6 birds), 10μg in Group 2 (6 birds) and 1μg in Group 3 (8 birds) by intramuscular injection. Birds in Group 4 (6 birds) were injected with placeboes (as control). 4 weeks post vaccination, each bird was challenged with 100 minimal egg infectious dose (MEID)of AIV A/Afril.Star/Eng Q/983/79(H7N1).1 week after challenge, all chickens were sampled with cloacal swab for virus isolation. During the experiment period of 6 weeks, the HI antibody to the AIV were evaluated weekly. Positive virus isolation was obtained from Group 2,3 and 4 (at 2/6,3/8 and 6/6, respectively), but not from Group 1(0/6).HI titer reached up to 64 at 1st week and 1024 at 2nd week post challenge not only in Group 1, but also in Group 2 and Group 3 (HI titer in Group 3 was 512). On the contrary, the maximum HI titer in Group 4 was only 16 and 128 at 1st and 2nd week postchallenge respectively.Results indicate that the pSVH7, designed as DNA vaccine, can elicit a firm protective immune response against H7 AIV infection, even at lower DNA dose.更多还原