State Key Laboratory for Diagnosis and Treatment of Infectious Disease, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China.
Vaccine. 2009 Dec 9;27(52):7451-8. doi: 10.1016/j.vaccine.2009.05.014. Epub 2009 May 29.
Several approaches are being taken worldwide to develop vaccines against H5N1 viruses; most of them, however, pose both practical and immunological challenges. One potential strategy for improving the immunogenicity of vaccines involves the use of alphavirus replicons and VP22, a herpes simplex type 1 (HSV-1) protein. In this study, we analysed the antigenic peptides and homogeneity of the HA sequences (human isolates of the H5N1 subtype, from 1997 to 2003) and explored a novel alphavirus replicon system of VP22 fused with HA, to assess whether the immunogenicity of an HA-based replicon vaccine could be induced and augmented via fusion with VP22. Further, replicon particles expressing VP22, and enhanced green fluorescent protein (EGFP) were individually used as controls. Cellular immune responses in mice immunised with replicons were evaluated by identifying specific intracellular cytokine production with flow cytometry (FCM). Animal-based experimentation indicated that both the IL-4 expression of CD4(+) T cells and the IFN-gamma expression of CD8(+) T cells were significantly increased in mice immunised with VPR-HA and VPR-VP22/HA. A dose titration effect vis-à-vis both IL-4 expression and IFN-gamma expression were observed in VPR-HA- and VPR-VP22/HA-vaccinated mice. Our results revealed that both VPR-VP22/HA and VPR-HA replicon particles presented a promising approach for developing vaccines against human-avian influenza, and VP22 could enhance the immunogenicity of the HA antigens to which it is fused.
目前全球正在采取多种方法来开发针对 H5N1 病毒的疫苗；然而，其中大多数方法都存在实际和免疫学方面的挑战。提高疫苗免疫原性的一种潜在策略涉及使用甲病毒复制子和 VP22，这是单纯疱疹病毒 1（HSV-1）的一种蛋白。在这项研究中，我们分析了 HA 序列的抗原肽和同源性（1997 年至 2003 年期间的人类 H5N1 亚型分离株），并探索了一种新型的 VP22 融合 HA 的甲病毒复制子系统，以评估基于 HA 的复制子疫苗的免疫原性是否可以通过与 VP22 融合来诱导和增强。此外，还分别使用表达 VP22 和增强型绿色荧光蛋白（EGFP）的复制子颗粒作为对照。通过流式细胞术（FCM）鉴定特异性细胞内细胞因子产生来评估用复制子免疫的小鼠的细胞免疫反应。基于动物的实验表明，用 VPR-HA 和 VPR-VP22/HA 免疫的小鼠中 CD4(+) T 细胞的 IL-4 表达和 CD8(+) T 细胞的 IFN-gamma 表达均显著增加。在 VPR-HA 和 VPR-VP22/HA 疫苗接种的小鼠中观察到剂量滴定效应，无论是在 IL-4 表达还是 IFN-gamma 表达方面。我们的结果表明，VPR-VP22/HA 和 VPR-HA 复制子颗粒均为开发针对人禽流感的疫苗提供了一种有前途的方法，并且 VP22 可以增强与其融合的 HA 抗原的免疫原性。
