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Studies on newly synthesized peptides having parasitocidal activity, and their mechanisms on host immune repsponses.

新合成的具有杀寄生虫活性的肽及其对宿主免疫反应的机制的研究。

基本信息

批准号：
07406014
负责人：
SAITO Atsushi
金额：
$ 23.04万
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 (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07406014/
关键词：
Neospora caninum Toxoplasma gondii Protective immunity vaccine

项目摘要

(1) Studies on newly synthesized peptidesNewly synthesized peptide (Obioactin to Obiopeptides) of the activity units which were isolated from cytokines as an immunoregulator were examined in the effect of Toxoplasma chronically infected animals. Mice chronically infected with Toxoplasma gondii were treated with cyclophosphamide (Cyp), Obiopeptide- 1 (Obio- 1) and/or anti-CD4 monoclonal antibody to determine the effect of these immunosuppressive agents on the cysts in the brain. In the brain of non-treate, and infected Cyp-Obi-1 treated mice, with hematoxyline-eosine staining or anti-Toxoplasma ABC labelling staining, large typically rounded tissue cysts were mostly detected, and in some regions dividing microcysts were also observed in this experimental studies. In contrast, brain tissue from Cyp only or anti-CD4 treated infected mice had multiple degenerated cysts of varied sizes in some brain regions, as well as clusters of microcysts, however, such change was more striking in the an … More ti-CD4 treated mice. Infected mice treated with a combination of Cyp and Obio- I showed a significantly higher survival of 80% compared to 20% survival in mice treated with Cyp only. These results indicate that reactivation of rupture of tissue cysts in mice treated with Cyp, chronically infected with Toxoplasma, might be mainly mediated by CD4 positive cells rather than other CD8 and CD5 positive cells.(2) Production of transgenic mice carrying protozoan geneSAG-1 (p30), the major surface protein of Toxoplasma gondii, 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. To generate transgenic mice carrying p30 gene, a 3.3kb DNA fragments, containing p30 cDNA fused with CAG promoter, that has been shown to direct a ubiquitous expression of a reporter gene in transgenic mice, were microinjected into one of the pronuclei of one-cell embryos of C57BL/6J, BA LB/c or Fl (C57BL/6J x C3H/He) mice. The embryos were transferred to the oviducts of pseudopregnant ICR mice. In the first series of experiment using inbred strains, two p30-positive founders (male C57BL/61 and female BALB/c) were obtained among 159 mice that developed from the injected eggs. Furthermore, we have obtained several P30-founder mice expressing the gene product and transmitting the gene to the next generation, by using Fl (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. Less

(1)新合成肽的研究从细胞因子中分离出活性单位的新合成肽（Obioactin到Obiopeptides）作为免疫调节剂，观察其对弓形虫慢性感染动物的作用。用环磷酰胺（Cyp）、Obio- 1和/或抗CD_4单克隆抗体治疗弓形虫慢性感染小鼠，观察免疫抑制剂对弓形虫脑内包囊的影响。在未处理的和感染Cyp-Obi-1处理的小鼠的脑中，用苏木精-曙红染色或抗弓形虫ABC标记染色，大多数检测到大的典型圆形组织囊肿，并且在本实验研究中还观察到在某些区域中分裂的微囊。相反，来自仅Cyp或抗CD 4治疗的感染小鼠的脑组织在某些脑区域中具有多个不同大小的变性囊肿，以及微囊肿簇，然而，这种变化在未感染小鼠中更显著。 ...更多信息 ti-CD 4处理的小鼠。用Cyp和Obio-I的组合治疗的感染小鼠显示出80%的显著更高的存活率，而仅用Cyp治疗的小鼠的存活率为20%。这些结果表明，Cyp治疗的小鼠，慢性感染弓形虫的组织囊肿破裂的再激活，可能主要是由CD 4阳性细胞介导的，而不是其他CD 8和CD 5阳性细胞。(2)弓形虫SAG-1（p30）基因是弓形虫的主要表面蛋白，被认为是弓形虫入侵宿主细胞过程中的重要配体。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。为获得p30基因的转基因小鼠，将一个3.3kb的DNA片段（含有p30 cDNA与CAG启动子的融合体）注射到C57 BL/6 J、BA LB/c和F1（C57 BL/6 J × C3 H/He）小鼠的一个单细胞胚胎原核中。将胚胎移植到假孕ICR小鼠的输卵管中。在使用近交系的第一系列实验中，在从注射的卵发育的159只小鼠中获得两个p30阳性建立者（雄性C57 BL/61和雌性BALB/c）。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，这是第一个转基因小鼠携带原生动物基因来自T. gondii。少