【摘要】 将从重组质粒pVAX1-HA中扩增的HA基因和从pVAX1-HA-CpG中切出的HA-CpG基因分别克隆入pcDNA3.1(+)载体中,获得重组质粒pcDNA3.1-HA和pcDNA3.1-HA-CpG。将上述重组质粒分别转染COS-7细胞,经间接免疫荧光试验检测发现HA基因可在COS-7细胞中表达。将重组质粒转入减毒鼠伤寒沙门菌SL7207,构建成携带DNA疫苗的重组沙门菌SL7207(pcDNA3.1-HA)和SL7207(pcDNA3.1-HA-CpG)。将重组菌分别以5×109CFU口服免疫1日龄鸡2次,重组菌免疫组产生的小肠黏膜抗体效价与空载体组及油乳剂灭活疫苗组间存在显著差异。攻毒免疫保护结果表明,SL7207(pcDNA3.1-HA-CpG)免疫组与空载体组之间存在显著差异,而SL7207(pcDNA3.1-HA)免疫组则与空载体组间无显著差异,说明CpG可增强DNA疫苗的免疫效果。更多还原

【Abstract】 The hemagglutinin protein(HA) gene of avian influenza virus was amplified from pVAX1-HA by PCR and sub-cloned into pcDNA3.1(+) vector.HA-CpG gene was also cloned into the pcDNA3.1(+).The two recombinant plasmids were transfected respectively into COS-7 cells,and identified for the transient expression of HA gene by indirect immunofluorescent assay.Finally,the two recombinant plasmids were transformed into the attenuated Salmonella typhimurium SL7207,and the recombinants were designated as SL7207(pcDNA3.1-HA) and SL7207(pcDNA3.1-HA-CpG),respectively.One-day-old commercial ISA brown chickens were immunized with one of the 2 recombinant bacteria at 5×109 CFU,respectively and boosted with the same dose two weeks later.No significant difference was observed in body weight among those groups.Intestinal mucosal immune response was observed in chickens immunized with one of the 2 recombinant bacteria on day 35,and their levels were significantly higher than those of the negative and positive controls.Compared with the negative control group,protective immunity induced by SL7207(pcDNA3.1-HA-CpG) provided significant protection,but SL7207(pcDNA3.1-HA) did not,indicating that the combination of CpG can enhance the immune response of the DNA vaccine deli-vered by the attenuated Salmonella.更多还原