Construction of a protozoan infection therapeutic vaccine development platform technology using antigen-displaying baculovirus

本研究为新孢子病成分疫苗的研制奠定了基础。5种候选抗原在家蚕中成功表达和纯化。构建了家蚕核多角病毒（Bombyx mori nuclear polyhedrovirus, BmNPV）颗粒，表达从家蚕幼虫中纯化的犬新孢子虫抗原（NcSAG1、NcSRS2和NcMIC3），用于小鼠免疫犬新孢子虫。与IgG1相比，显示ncsag1的BmNPV颗粒免疫小鼠主要产生抗原特异性IgG2a， ifn - γ的诱导占主导地位，表明显示抗原的BmNPV颗粒可以在小鼠中引发Th1免疫反应。半定量PCR分析显示，用蚕纯化的BmNPV抗原颗粒免疫小鼠，可部分保护小鼠免受脑犬奈尔病毒感染。这些结果表明，从家蚕中纯化的显示抗原的BmNPV颗粒可以为新一代犬瘟病毒疫苗的制备提供一种替代方法。

In this study, we build the foundation of component vaccine development of neosporosis. Five candidate antigens were successfully expressed and purified in silkworm. Bombyx mori nucleopolyhedrovirus (BmNPV) particles displaying Neospora caninum antigens (NcSAG1, NcSRS2 and NcMIC3) purified from silkworm larvae were constructed to vaccinate mice against N. caninum. Antigen-specific IgG2a was predominantly produced in mice by immunization with NcSAG1-displaying BmNPV particles compared to IgG1, and induction of IFN-gamma was dominant, indicating that antigen-displaying BmNPV particles can elicit a Th1 immune response in mice. Semi-quantitative PCR analysis revealed that immunization with each antigen-displaying BmNPV particle purified from silkworms partially protected mice from cerebral N. caninum infection. These results suggest that antigen-displaying BmNPV particles purified from silkworms can provide an alternative method of a new generation of N. caninum vaccines.