Plant expression of antigens of animal pathogens and its application for oral vaccination

该项目旨在表达动物病原微生物的基因，并开发与细胞因子相结合的鼻腔或口腔注射形式的黏膜疫苗。以传播各种原生动物寄生虫的硬蜱唾液抗原为模型抗原进行了研究。利用农杆菌系统将牛转化生长因子β基因导入烟草中，并证实其在再生植株中的表达。豆胺类信号序列的加入可增强其表达。我们还在烟草植株中表达了牛IL-1和IL-2。通过体外实验证实了这些细胞因子的生物学活性。克隆了硬蜱粘蛋白、丝氨酸蛋白酶及其抑制物(丝氨酸)的基因，并对它们的分子结构进行了研究。对这些分子的生物活性也进行了验证。重组水泥蛋白免疫兔后，可抑制硬蜱的侵染，表明重组水泥蛋白是一种很好的疫苗商品化候选材料。

This project was aiming at expression of genes from animal pathogenic microbes, and development of mucosal vaccine as an injectable form into nasal or oral cavities in combination with cytokines. As model antigens, salivary antigens of ticks that transmit various protozoan parasite were investigated. Those antigens combined with cytokines such as interleukin-1 or -2 will be used as tick waccines.We introduced a bovine transforming growth factor beta gene into tobacco by using Agrobacterium system, and confirmed its expression in regenerated plant. Expression was enhanced by addition of legumine signal sequence. We also expressed bovine IL-1 and IL-2 in tobacco plants. Biological activities of these cytokines were confirmed by in vitro assays.Genes for tick cement proteins, serine proteinases, and their inhibitors (serpin) were cloned and their molecular structures were investigated. Biological activities of these molecules were also demonstrated. Vaccination of rabbit with recombinant cement proteins inhibited tick infestation, which suggested these proteins are good candidate for commercial production of tick vaccines.