Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Viral Immunol. 2011 Aug;24(4):311-9. doi: 10.1089/vim.2011.0016.
Influenza virus-like particles (VLPs) are effective vaccines against influenza infection, which can be produced either in insect cells by recombinant baculovirus (BV) infection or in mammalian cells by DNA plasmid transfection. However, VLPs produced from baculovirus/insect cells are difficult to purify due to baculovirus contamination; VLPs produced by plasmid transfection are limited by scale-up capability. In this study, a BacMam BV, in which three CMV-promoters drive the hemagglutinin, neuraminidase, and matrix of influenza virus was constructed. This baculovirus can deliver these genes into mammalian cells/hosts and subsequently influenza VLPs can be produced and secreted from transduced cells. Transduction conditions were optimized and influenza VLPs were purified from transduced 293T cells. Mice were vaccinated with BV transduction-produced VLPs, plasmid transfection-produced VLPs, and BacMam BV. Two vaccinations of each vaccine induced high hemagglutination-inhibition (HAI) titers and prevented influenza virus infection. In contrast, following a single vaccination, all mice vaccinated with each vaccine had significantly lower lung viral titers compared to unvaccinated mice. Remarkably, mice vaccinated with a single dose of BV transduction-produced VLPs survived challenge, whereas mice vaccinated with one dose of BacMam BV- or plasmid transfection-produced VLPs had 60-80% survival. This finding is particularly significant for producing easily purified VLPs. The BacMam system is an alternative strategy for VLP production, which is easy to scale up and purify. Besides, BacMam BV can be used as a gene delivery vector to produce VLPs in vivo, to stimulate immune responses.
流感病毒样颗粒（VLPs）是预防流感感染的有效疫苗，可通过重组杆状病毒（BV）感染昆虫细胞或通过 DNA 质粒转染在哺乳动物细胞中产生。然而，由于杆状病毒污染，从杆状病毒/昆虫细胞中产生的 VLPs 难以纯化；通过质粒转染产生的 VLPs受到规模扩大能力的限制。在本研究中，构建了一种 BacMam BV，其中三个 CMV 启动子驱动流感病毒的血凝素、神经氨酸酶和基质。这种杆状病毒可以将这些基因递送到哺乳动物细胞/宿主中，随后可以从转导的细胞中产生和分泌流感 VLPs。优化了转导条件，并从转导的 293T 细胞中纯化了流感 VLPs。用 BV 转导产生的 VLPs、质粒转染产生的 VLPs 和 BacMam BV 对小鼠进行了疫苗接种。每种疫苗接种两次均可诱导高血凝抑制（HAI）滴度并预防流感病毒感染。相比之下，单次接种后，与未接种疫苗的小鼠相比，所有接种每种疫苗的小鼠肺部病毒滴度均显著降低。值得注意的是，单次接种 BV 转导产生的 VLPs 的小鼠能够存活下来，而接种单次剂量的 BacMam BV 或质粒转染产生的 VLPs 的小鼠的存活率为 60-80%。这一发现对于生产容易纯化的 VLPs 尤其重要。BacMam 系统是生产 VLPs 的替代策略，易于扩大规模和纯化。此外，BacMam BV 可用作体内基因传递载体，以刺激免疫反应。
