The Wistar Institute, Philadelphia, PA, USA.
Mol Ther. 2013 Mar;21(3):696-706. doi: 10.1038/mt.2012.248. Epub 2012 Dec 11.
To determine if an ordered and repetitive display of an epitope promoted induction of superior antibody responses, we compared B-cell responses to an influenza A virus epitope that was either encoded as a transgene by an adenovirus (Ad) vector or expressed on the vector's surface. To this end, we constructed a panel of influenza A virus vaccines based on chimpanzee-derived replication-defective adenovirus (AdC) vectors of serotype SAd-V25 also called AdC68. AdC68 vectors were modified to express a linear B-cell epitope of the ectodomain of matrix 2 (M2e) within variable regions 1 (VR1) or 4 (VR4) of the adenovirus hexon. Additional vectors with wild-type or M2e-modified hexon encoded M2e fused to the influenza A virus nucleoprotein (NP) as a transgene product. Hexon-modified vectors were tested for immunogenicity and efficacy in mice in comparison to vectors with native hexon expressing the M2e-NP fusion protein. Upon priming, vectors expressing M2e within VR1 of hexon induced M2e-specific antibody responses of higher magnitude and avidity than those carrying M2e within VR4 or vectors expressing the M2e as part of a transgene product. CD8(+) T-cell responses to the transgenic NP were comparable between vectors. M2e-specific antibody responses could be boosted by a second dose of the VR1 hexon-modified vector but not by repeated immunization with the VR4 hexon-modified vector.
为了确定抗原表位的有序和重复展示是否能促进更好的抗体反应，我们比较了甲型流感病毒表位在腺病毒（Ad）载体中的转导表达和在载体表面的展示对 B 细胞反应的影响。为此，我们构建了一组基于黑猩猩来源的复制缺陷型腺病毒（AdC）载体 SAd-V25（也称为 AdC68）的甲型流感病毒疫苗。AdC68 载体经过修饰，在腺病毒六邻体的可变区 1（VR1）或 4（VR4）内表达了基质 2（M2e）的线性 B 细胞表位。其他载体则具有野生型或 M2e 修饰的六邻体，编码 M2e-核蛋白（NP）融合蛋白作为转基因产物。我们比较了这些带有 M2e 修饰的六邻体的载体与表达 M2e-NP 融合蛋白的天然六邻体载体在小鼠中的免疫原性和功效。在初次免疫后，表达 M2e 的 VR1 六邻体载体诱导的 M2e 特异性抗体反应的幅度和亲和力高于表达 M2e 的 VR4 载体或作为转基因产物表达 M2e 的载体。载体间对转基因 NP 的 CD8+T 细胞反应相当。VR1 六邻体修饰载体的第二次免疫可以增强 M2e 特异性抗体反应，但 VR4 六邻体修饰载体的重复免疫则不能。
