国家自然科学基金资助项目(30700743)
This work was supported by a grant from The National Natural Science Foundation of China (30700743)
应用反向遗传学技术,选择冷适应、温度敏感、减毒的A/Ann Arbor/6/60 ca (H2N2)型流感病毒的6个内部基因为骨架,与A/California/07/2009株流感病毒2个抗原基因HA、NA分别克隆到polⅠ-polⅡ转录表达载体pAD3000中,构建8个转录表达载体重组质粒,共转染Vero细胞,获得重配A/California/07/2009ca株流感病毒.重配病毒的TCID50为7.5,病毒传4代后其血凝素(HA)滴度稳定在1∶256,半数感染剂量EID50为8,鸡胚传20代,经RT-PCR鉴定未发现重组病毒基因突变,电镜观察重配病毒符合流感病毒的主要特征;蔗糖纯化的病毒经肌肉注射(灭活)及滴鼻(减毒活病毒)两种途径免疫BALB/c小鼠,结果显示:滴鼻免疫和肌肉注射都可以产生较高效价的血凝抑制(HI)抗体,肌肉注射组产生的HI抗体略高(P = 0.044),但肌肉注射组检测不到高效价IgA抗体;滴鼻免疫组鼻冲洗液中可以检测到高效价的IgA抗体,同型病毒感染后,IL-1β、TNFα、IFN-α等前炎因子分泌较早,且高于肌肉注射组(P < 0.05),可见,喷鼻减毒疫苗比灭活全病毒疫苗能更好地激发黏膜免疫反应.通过对小鼠各个器官病毒载量的检测发现,4天后鼻腔、气管、脑、肺、脾脏没有病毒存在,证明减毒活疫苗株在小鼠上是安全的.以上数据可以初步断定,重组病毒有作疫苗候选株的可能,而且喷鼻疫苗具有降低免疫剂量、同时激活体内体液免疫和细胞免疫的功能.
Six internal protein gene segments of attenuated, cold-adapted(ca), temperature -sensitive (ts) influenza A/Ann Arbor/6/60 ca (H2N2) and HA, NA gene segments of A/California/07/2009ca were introduced to plasmid pAD3000 carrying polⅠ and polⅡ promoters, and rescued the reassortant virus from Vero cell using reverse genetics technology. The reassortant has the attenuate characters, ca and ts, the TCID50 is 7.5, HA titer maintain at 1∶256 and EID50 is 8 which was detected using SPF eggs. The stable of reassortant is determined by RT-PCR gene segments from virus which were propagated in eggs. The morphology of reassortant conform the wild type virus. In order to test the immunogenicity, the reassortant viruses were purified. Mice were intranasally immunized and intramuscular injected with inactive whole virus as control. The high HI titer can be detected in both groups, seems hinger in i.m.(intramuscular) immunized groups (P=0.044), but higher IgA titer can only detected in i.n.(intranasal) immunized group. Compared with i.m. immunized group, higer pro-inflammation cytokines IL-1β, TNFα, IFN-α were tested in i.n. groups, means faster and stronger mucosal immune response was induced. Virus load were detected in lung, brain, spleen 4 days after immunization to determine the safety of reassortant as vaccine candidate, no detectable virus were found. All results show that the vaccine candidate can be used for vaccine production.
段跃强,罗德炎,邢 丽,杨鹏辉,赵忠鹏,贾卫红,李培锋,王希良. A/California/07/2009亚型猪流感冷适应减毒疫苗株的拯救及免疫效果评价[J].生物化学与生物物理进展,2010,37(12):1289-1295
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