STUDIES ON SCHISTOSOMIASIS AND CHAGAS DISEASE

血吸虫病和恰加斯病的研究

• 批准号: 6234767
• 负责人: CLINT E CARTER
• 金额: $ 8.03万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-03-01 至 1998-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6234767
• 关键词: Brazil; CD44 molecule; DNA; Trypanosoma cruzi; body fluids; cellular immunity; colon disorder; cooperative study; esophagus disorder; flow cytometry; histocompatibility antigens; histopathology; human tissue; humoral immunity; immunocytochemistry; in situ hybridization; inflammation; laboratory mouse; lymphocyte; microorganism genetics; myocardium disorder; nucleic acid sequence; pericardium; phenotype; polymerase chain reaction; trypanosomiasis

Chagas' Disease, parasitic infection caused by the protozoan Trypanosoma cruzi, affects 16-18 million people primarily in Central and South America. While autochthonous cases are rare in the United States, Chagas' Disease may represent an increasing public health problem with increasing immigration of Latin Americans. The major causes of morbidity and mortality in Chagas' Disease is secondary to cardiac and gastrointestinal involvement. Both occur, late, 10 or more years after acute infection. Pathologically both exhibit focal lymphocytic infiltrates which are associated with scarring and loss of myocardial cells in Chagasic cardiomyopathy and neuronal degeneration leading to deinnervation and pathologic dilatation in Chagasic megaesophagus and megacolon. In both Chagasic cardiomyopathy and intestinal Chagas', organisms are rarely found which has questioned the role of parasite persistence in late complications of infection. Chagasic cardiomyopathy and megasyndromes usually do not occur in the same patient and exhibit striking geographic variation in their relative frequency. Recent molecular genetic studies have demonstrated the presence of a 188-bp segment of a repetitive 195-bp DNA sequence adjacent to inflammatory foci in 18 or 21 paraffin-embedded autopsy sections of heart muscle from 7 patients with Chagasic cardiomyopathy. We propose to extend these investigations to identify the cells containing parasite DNAs using in situ PCR techniques and to study the form of parasite DNA by amplifying other T. cruzi-specific DNA sequences. In megasyndromes where inflammatory foci are much more dispersed we will amplify the 195 base repetitive DNA sequence in scrapings of lesions microdissected from H & E-stained sections of esophagus or colon obtained at autopsy or surgery. One possible explanation for the variation in the relative geographic distribution in the late cardiac and gastrointestinal manifestations of Chagas' Disease is that different pathologic mechanisms of injury may be at work. We have previously identified a granzyme-positive CD8 T-cell as the predominant cell in inflammatory cardiac lesions. Additional studies have demonstrated upregulation of MHC class I molecules on myocardial cells and enhanced-expression of MHC class II antigens, E Selectin and CD44 on endothelial cells. We would extend these immunohistochemical studies to the megasyndromes. Finally, epicardial inflammation with pericardial effusion is an almost invariant finding in Chagasic cardiomyopathy. These effusions contain viable lymphocytes and have been recently shown to contain T. cruzi-specific antibodies. Pericardial fluid could provide a window to study humoral and cellular immune responses in Chagasic cardiomyopathy. We would extend earlier studies of humoral responses in pericardial fluid first by characterizing lymphocyte populations immunohistochemically and then using cloning techniques to expand B- and T-cell lymphocyte populations for investigation of B-cell specificity and T-cell function and receptor specificity.

恰加斯病，由原生动物锥虫引起的寄生虫感染 cruzi，主要影响中部和南部地区的 16-1800 万人 美国。 虽然本土病例在美国很少见， 恰加斯病可能是一个日益严重的公共卫生问题 拉丁美洲移民的增加。 发病的主要原因 恰加斯病的死亡率继发于心脏病和 胃肠道受累。 两者都发生在较晚的10年或更长时间之后 急性感染。 病理学上均表现出局灶性淋巴细胞 与疤痕形成和心肌损失相关的浸润 恰加斯心肌病中的细胞和神经元变性导致 恰加斯巨食管的去神经支配和病理性扩张 巨结肠。 在恰加斯心肌病和肠恰加斯病中， 很少发现生物体，这对寄生虫的作用提出了质疑 感染晚期并发症的持续存在。 恰加斯心肌病 和巨型综合症通常不会发生在同一患者身上并且表现出 它们的相对频率存在显着的地理差异。 最近的 分子遗传学研究表明存在 188 bp 邻近炎症病灶的 195 bp DNA 重复序列片段 来自 7 个国家的 18 或 21 个石蜡包埋的心肌尸检切片 恰加斯心肌病患者。 我们建议延长这些 鉴定含有寄生虫 DNA 的细胞的研究 原位PCR技术并通过扩增来研究寄生虫DNA的形态 其他 T. cruzi 特异性 DNA 序列。 在巨型综合症中 炎症灶更加分散，我们将放大 195 碱基 从 H & 显微解剖的病变刮片中的重复 DNA 序列 在尸检或手术中获得的食管或结肠的 E 染色切片。 相对地理差异的一种可能解释 晚期心脏和胃肠道表现的分布 恰加斯病是一种不同的病理损伤机制 在上班。 我们之前已经鉴定出颗粒酶阳性 CD8 T 细胞 作为炎症性心脏病变的主要细胞。 额外的 研究表明 MHC I 类分子的上调 心肌细胞和 MHC II 类抗原 E 的表达增强 内皮细胞上的选择素和 CD44。 我们将扩展这些 对巨型综合征的免疫组织化学研究。 最后是心外膜 炎症伴心包积液几乎是一个不变的发现 查加斯心肌病。 这些积液含有活的淋巴细胞和 最近已被证明含有克氏锥虫特异性抗体。 心包液可以提供研究体液和细胞的窗口 恰加斯心肌病的免疫反应。 我们会提前延长 首先通过表征来研究心包液中的体液反应 淋巴细胞群体免疫组织化学，然后使用克隆 扩大 B 细胞和 T 细胞淋巴细胞群的技术 B 细胞特异性以及 T 细胞功能和受体的研究 特异性。