Developmental biotechnological and molecular immunological analysis of host defense mechanisms against protozoan infection

宿主针对原生动物感染的防御机制的发育生物技术和分子免疫学分析

• 批准号: 11460144
• 负责人: NAGASAWA Hideyuki
• 金额: $ 5.25万
• 依托单位: Obihiro University of Agriculture and Veterinary Medicine
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11460144/
• 关键词: protozoan diseases; Toxoplasma gondii; Neospora caninum; Cryptosporidium parvum; Transgenic; apoptosis; protective immunity; P0 protein

Protozoan parasites are most important causative of infectious diseases in the world. The subjectives of this study have focused on the prevention of protozoan diseases through the studies on biological substances and products derived from protozoa themselves, as well as on host defense mechanisms. Genetically modified animals such as transgenic mice and knockout mice are known to be powerful tools for analysis of gene function in vivo.(1) Identification of specific molecules from Toxoplasma gondii, Babesia sp., Trypanosoma sp., Neospora caninum, Cryptosoridium parvum using molecular biological techniques.(2) Localization of immunogenic molecules from protozoan parasites using IFA, confocal leser microscope, immuno-EM.(3) Analysis of host immune responses using knockout mice as well as transgenic mice such as SAG-1 transgenic mouse, IFN-γ knockout mouse, scavenger receptor (SR) knockout mouse and TNF-α knockout mouse.SAG-1 (p30), the major surface protein of Toxoplasma gondii, is consi … More dered as an important ligand in the process of host cell invasion. To analyze the mechanism of host cell irivasion and immune response in toxoplasmosis, we have established transgenic mice carrying p30 for the first time in the world. Moreover, many kind of knockout mice deficient in cytokines or receptors have been used for analysis of the host defense mechanisms against protozoan infection in our research center.It was found that among surface molecules of antigen presenting cells (APC), class II, CD80 and CD86 have a crucial role for protective immune responses against protozoan infection. Although expression level of CD28 on T cells was not changed after infection, effective molecules to activate T cells, that is class II, CD80 and CD86 on the APC, were significantly detectable with high expression. SAG-1 (p30) is considered as an important ligand in the process of host cell invasion. If this protein is produced by host cells and interfere with that of parasites, then the host will become resistant to parasite invasion. Or, it may become more susceptible to infection due to the lack of immune response against p30 antigen. We have obtained several P30-founder mice expressing the gene product and transmitting the gene to the next generation, by using F1 (C57BL/6J x C3H/He) embryos. As far as we are aware, this is the first transgenic mice bearing a protozoan gene derived from T. gondii. We found that P30 molecule is one of important trigger to introduce the host immune responses against Toxoplasma infection. Furthermore, apoptosis of host cells is one of escape mechanisms of protozoan parasite against host protective immunity. Less

原虫是世界上最重要的传染病病原。本研究的主题集中在通过研究原生动物自身衍生的生物物质和产物以及宿主防御机制来预防原生动物疾病。转基因小鼠和基因敲除小鼠等转基因动物是研究体内基因功能的有力工具。(1)弓形虫巴氏亚种特异性分子的鉴定锥虫属，犬新孢子虫、微小隐孢子虫的分子生物学研究。(2)免疫荧光、激光共聚焦显微镜、免疫电镜对原虫免疫原性分子的定位。(3)用基因敲除小鼠和转基因小鼠如SAG-1转基因小鼠、IFN-γ基因敲除小鼠、清道夫受体（SR）基因敲除小鼠和TNF-α基因敲除小鼠分析宿主免疫应答。 ...更多信息 作为一种重要的配体参与了宿主细胞的侵袭过程。为探讨弓形虫病宿主细胞侵袭和免疫应答机制，我们在国际上首次建立了p30转基因小鼠。此外，本研究中心还利用多种细胞因子或受体缺陷的基因敲除小鼠研究了宿主抗原虫感染的防御机制，发现在抗原呈递细胞（APC）的表面分子中，Ⅱ类分子CD 80和CD 86在机体抗原虫感染的保护性免疫应答中起着重要作用。虽然感染后T细胞上的CD 28表达水平没有改变，但活化T细胞的有效分子，即APC上的II类CD 80和CD 86，在高表达下显著检测到。SAG-1（p30）被认为是宿主细胞侵袭过程中的重要配体。如果这种蛋白质由宿主细胞产生并干扰寄生虫的蛋白质，那么宿主将对寄生虫入侵产生抵抗力。或者，由于缺乏针对p30抗原的免疫应答，它可能变得更容易感染。利用F1（C57 BL/6 J × C3 H/He）胚胎获得了几只表达该基因产物并将该基因传递给下一代的P30-founder小鼠。据我们所知，这是第一只携带来自T。刚地。我们发现P30分子是介导宿主抗弓形虫感染免疫应答的重要触发因子之一。此外，宿主细胞凋亡也是寄生虫逃避宿主保护性免疫的机制之一。少

项目成果

Nishikawa, Y. et al.: "Interferon-gamma-induced apoptosis in host cells infected with Neospora caninum"Parasitology. 123. 25-31 (2001)

Nishikawa, Y. 等人：“感染犬新孢子虫的宿主细胞中干扰素γ诱导的细胞凋亡”寄生虫学。

Inoue,N. et al.: "Novel species specific antigens of Trypanosoma congolense and their different localization among life-cycle stages."J.Vet.Med.Sci.. 62. 1041-1045 (2000)

井上，N.

Tanaka T.et al.: "Expression of Babesia equi merozoite antigen-2 by recombinant baculovirus and its use in the ELISA"Int. J. Parasitol.. 29. 1803-1808 (1999)

Tanaka T.et al.：“重组杆状病毒表达马贝贝虫裂殖子抗原 2 及其在 ELISA 中的应用”Int.

Ikadai H.et al.: "Inhibitory effect of monoclonal antibodies on the growth of Babesia caballi"Int. J. Parasitol.. 29. 1785-1791 (1999)

Ikadai H.等：“单克隆抗体对巴贝虫生长的抑制作用”Int.

Mishima, M. et al.: "Modified protection against Toxoplasma gondii lethal infection and brain cyst formation by vaccination with SAG2 and SRS1"J.Vet.Med.Sci.. 63(4). 433-438 (2001)

Mishima, M. 等人：“通过接种 SAG2 和 SRS1，改进了对弓形虫致命感染和脑囊肿形成的保护”J.Vet.Med.Sci. 63(4)。