Aβ3-10多价腺病毒疫苗鼻黏膜免疫BALB/c鼠的免疫原性鉴定及Aβ蛋白表达检测

Identification of the immunogenicity of multivalence Aβ3-10 adenovirus vaccine and expression of Aβ in nasal mucosal in BALB/c mice

关键词:  阿尔茨海默病  腺病毒载体疫苗  免疫原性  Aβ

Key words:  Alzheimer's disease  adenovirus vaccine  immunogenicity  β-amyloid

摘要:

目的　探讨Aβ_3-10多价腺病毒疫苗鼻黏膜免疫BALB/c鼠的免疫原性鉴定及蛋白表达。　方法　18只12月龄BALB/c小鼠，随机分为3组，分别为Ad-Aβ_(3-10)10-CpG组，空腺病毒载体组和Aβ_1-42组，分别以Aβ_3-10多价腺病毒疫苗Ad-Aβ_(3-10)10-CpG鼻黏膜免疫、空腺病毒载体鼻黏膜免疫、Aβ_1-42肌内注射免疫。各组均每2周免疫1次，共免疫6次。ELISA法检测血清抗Aβ抗体滴度及亚型，免疫组化法检测免疫后的BALB/c小鼠抗血清能否与转基因鼠脑内Aβ斑块结合，免疫组化法检测鼻黏膜内Aβ蛋白的表达。　结果　Ad-Aβ_(3-10)10-CpG组和Aβ_1-42组抗体滴度随着免疫次数逐渐增加。6次免疫后Ad-Aβ_(3-10)10-CpG组血清中抗Aβ抗体滴度为（83.71±16.69）μg/mL，明显高于空载体组（P<0.01），而低于Aβ_1-42组（P<0.05）。Ad-Aβ_(3-10)10-CpG组和Aβ_1-42组的IgG1/ IgG2a比值分别为10.85±2.02和1.95±1.82，Ad-Aβ_(3-10)10-CpG组IgG1/IgG2a比值明显高于Aβ_1-42组（P<0.05）。Ad-Aβ_(3-10)10-CpG组和Aβ_1-42组小鼠的抗血清能和转基因鼠脑内的Aβ斑块结合。Ad-Aβ_(3-10)10-CpG组鼻黏膜内可以检测到Aβ蛋白表达，而其他各组小鼠鼻黏膜内未检测到Aβ蛋白表达。　结论　Aβ_(3-10)多价腺病毒疫苗鼻黏膜免疫主要产生Th2型免疫应答，减少了由T细胞介导的免疫应答引起的炎症反应。

Abstract:

Objective　 To identify the immunogenicity of the multivalence Aβ_(3-10) adenovirus vaccine and to detect the expression of Aβ in nasal mucosa of the BALB/c mice. 　Methods 　Eighteen twelve-month old BALB/c mice were divided into three groups, Ad-Aβ_(3-10)10-CpG group, empty vector group and Aβ_1-42group. They were immunized with recombinant adenovirus vaccine Ad-Aβ_(3-10)10-CpG by intranasal inoculation, with intranasal inoculation empty adenoviral vector and with intramuscularly injection Aβ_1-42, respectively. Titers of anti-Aβ antibody and isotypes of immunoglobin in sera were determined with ELISA. The immunoreactivity of antisera to amyloid plaque and the expression of Aβ in nasal mucosal were detected by immunohistochemistry.　Results　 Sera from Ad-Aβ_(3-10)10-CpG group and Aβ_1-42 group showed a steady increase in anti-Aβ antibody titer with each boost. The average anti-Aβ antibody titer in Ad-Aβ_(3-10)10-CpG group （83.71±16.69)μg/mL after six times of immunization was greater than that in empty vector group（P<0.01）and lower than that in Aβ_1-42 group（P<0.05）. IgG1/IgG2a ratio was 10.85±2.02 in Ad-Aβ_(3-10)10-CpG group and 1.95±1.82 in Aβ_1-42 group(P<0.05). Sera from Ad-Aβ_(3-10)10-CpG group and Aβ_1-42 group was able to bind to Aβ plaques in brain sections of transgenic mouse. Expression of Aβ in the nasal mucosa was observed in Ad-Aβ_(3-10)10-CpG group, while not in other groups. 　Conclusions 　Intranasal inoculation with the recombinant adenovirus vaccine Ad-Aβ_(3-10)10-CpG could induce Th2-polarized immune response in the wild-type mice. The adenovirus vaccine Ad-Aβ_(3-10)10-CpG had low potential to cause T cell-mediated autoimmune response. This could provide the basis for the next step researches in transgenic mice.