Induction mechanisms of mucosal immune response in intramucosal parasitic protozoan infection

本研究旨在阐明寄生虫侵袭组织中粘膜免疫反应的诱导机制以及全身免疫反应与细胞免疫反应之间的关系。分析微小隐孢子虫可溶性抗原的特性。在感染微小隐孢子虫的犊牛粪便上清液中检测到可溶性抗原。通过对弓形虫肠道上皮期抗原的分析，构建了弓形虫肠道上皮期寄生虫的cDNA文库，并通过免疫筛选获得了14个克隆。序列分析和功能分析显示与14-3-3蛋白相似。在感染兔的胆汁中检测到斯氏艾美耳球虫可溶性抗原的特性以及感染和免疫后的免疫反应。感染斯氏艾美耳球虫的兔产生了对该抗原的抗体。绵羊新孢子虫分离株的致病性及对小鼠感染的免疫应答。免疫缺陷小鼠表现出死亡的临床迹象。具有免疫能力的小鼠没有任何临床症状，并产生了针对寄生虫的抗体。

This study was aimed to clarify induction mechanism of mucosal immune responses in tissues invaded by parasitic protozoa and relationship between systemic immune responses and cell mediated immune responses. In addition, specific antigen molecules derived from the parasites were also attempted to analyze the immunologic and biological characteristics.Analysis of characteristics of Cryptosporidium parvum soluble antigenSoluble antigen was detected in the supernatant of feces of calves infected with C. parvum. The infected calves produced IgA antibody against the copro-antigen during convalescent phase of the infection.Analysis of feline enteroepithelial stages antigens in Toxoplasma gondiiFrom enteroepithelia stage parasites of T. gondii, cDNA library was constructed and 14 clones were isolated by immunoscreening. Sequence analysis and function assay showed similarity to 14-3-3 protein.Characteristics of Eimeria stiedai soluble antigen and immune responses in rabbits either infected or immunized with the antigenSoluble antigen was detected in the bile of infected rabbits. Rabbits infected with E. stiedai produced antibody to the antigen. Rabbits immunized with the soluble antigen showed resistant to the infection.Pathogenicity of Neospora caninum isolated from sheep and immune responses to the infection in miceNeospora caninum was isolated from sheep and the pathogenicity was examined by experimental infection in mice. Immunodeficient mice showed clinical signs to die. Immunocompetent mice showed without any clinical signs and produce antibody against the parasites.