免疫增强剂CpG DNA重组质粒对不同日龄SPF鸡H9亚型禽流感灭活疫苗免疫效应的影响

Effects of Immune Enhancer CpG DNA Recombinant Plasmid on Immune Response of H9 Subtype AIV Inactivated Vaccine in Different Day-old SPF Chickens

为分析CpG基序寡聚脱氧核苷酸(CpG DNA)对H9亚型禽流感病毒(AIV-H9)灭活疫苗的免疫增强作用,利用商品化的含有CpG DNA的重组质粒作为AIV-H9灭活抗原的免疫佐剂,经肌内注射1、7、21日龄的SPF鸡,通过检测鸡血清中HI抗体和外周血淋巴细胞CD4、CD8基因相对表达量,分析CpG DNA重组质粒对不同日龄SPF雏鸡首次免疫AIV-H9灭活疫苗免疫效果的影响。结果显示:1、7和21日龄SPF鸡首免后,CpG DNA免疫增强剂添加组的HI抗体滴度明显高于未添加组(P≤0.05),HI抗体峰值滴度升高了近2log2滴度,差异极显著(P≤0.01),且上升速度更快;CpG DNA免疫增强剂添加组,在21日龄免疫时的免疫效果明显优于1日龄和7日龄免疫组,表现为HI抗体上升速度更快,峰值更高,离散度更小;首免3周后,7日龄和21日龄SPF鸡CpG DNA免疫增强剂添加组的CD4、CD8基因相对表达量均高于同日龄未添加组,且明显高于1日龄SPF鸡组(P≤0.01)。结果表明,CpG DNA能显著增强鸡对AIV-H9灭活疫苗的特异性体液免疫反应,可以作为高效的免疫增强剂,尤其在21日龄使用时免疫效果更好。本研究为CpG DNA重组质粒在禽流感疫苗上的联合应用以及研制新型复合佐剂疫苗提供了依据。

In order to analyze the immune enhancement effect of motifs oligodeoxynucleotides(CpG DNA)on the inactivated vaccines against avian influenza virus H9 subtype(AIV-H9),SPF chickens at the ages of 1,7 and 21 days were intramuscularly injected using the commercial recombinant plasmid containing CpG DNA as the immune adjuvant of AIV-H9 inactivated antigen,then the effects of CpG DNA recombinant plasmid on different day-old SPF chickens with first vaccination were analyzed through detecting relative expression of HI antibody in chicken serum and CD4 and CD8 genes in peripheral blood lymphocytes. The results showed that,after first vaccination in the SPF chickens at the ages of 1,7 and 21 days,the HI antibody titers in the CpG DNA immune enhancer groups were significantly higher than that without additive(P ≤ 0.05),the HI peak antibody titer increased by nearly 2log2,with extremely significant difference(P ≤ 0.01)and faster speed of rising;for the CpG DNA immune enhancer groups,the immune effect in SPF chickens at the age of 21 days was significantly better than that in those at the ages of 1 and 7 days,as HI antibody rose faster with higher peak value and smaller dispersion;three weeks after the primary vaccination,the relative expression of CD4 and CD8 genes in SPF chickens at the ages of 7 and 21 days was higher than in group at the same age without additive,and significantly higher than that in the 1-day-old ones(P ≤ 0.01). It was concluded that the specific humoral immune response of chickens to AIV-H9 inactivated vaccines was greatly enhanced by CpG DNA that could be used as an effective immuno-enhancer,especially for those at 21 days old. A basis was thus provided for future combined application of CpG DNA recombinant plasmid in vaccines against avian influenza and the development of any new compound adjuvant vaccines.