NATURAL IMMUNITY TO ENTAMOEBA HISTOLYTICA

溶组织内阿米巴是一种肠道原生动物， 是世界人口的主要寄生虫原因之一， 世界范围内的死亡 最近，一些重要的阿米巴抗原已经被发现， 已被分离、表征和克隆，包括170 kDa重链 半乳糖可降解粘附蛋白（GIAP）的亚基，29 kDa 肝细胞特异性表面抗原，主要半胱氨酸蛋白酶， E.组织溶解性和高度保守的125 kDa表面抗原。 然而，在这方面， 在研制阿米巴病疫苗之前，我们必须 进一步了解对这种寄生虫的天然免疫力。 的 这项提案的总体目标是确定自然免疫力是否 在侵袭性阿米巴病和无症状肠道 感染，如果是这样，以表征特定的免疫反应 关联的. 待检验的假设有：1）侵入性 阿米巴病之后是针对侵袭性阿米巴病的保护性免疫 和无症状肠道感染E.溶组织的 2)消除 无症状致病性和非致病性E.肠溶组织痛 感染后，免疫力持续数月至数年， 感染; 3）对侵袭性阿米巴病的免疫力取决于 持续的抗原特异性细胞介导的免疫（CMI）应答，免疫 肠道感染需要类似的特异性sIgA反应。 本提案的具体目的是确定：1） 血清学阳性者中侵袭性阿米巴病和无症状肠道感染 个体治愈阿米巴肝脓肿和对照; 2）如果有 阿米巴感染或疾病之间的关联; 3）宿主 无症状E.溶组织感染及其 与感染清除率的关系;以及4）复发性 无症状感染，其与宿主免疫反应的相关性，以及 免疫力是否是菌株特异性的。 这将通过 100例阿米巴肝脓肿治愈，900例阿米巴肝脓肿治愈， 在医学研究理事会（纳塔尔）和 南非德班的爱德华七世国王医院。 1000人中的每一个 受试者将每三个月进行一次随访， 临床状况、E.溶组织性肠道感染， 粪便抗原的培养和直接检测以及 感染菌株 此外，血清粘附蛋白测定 抗原血症，血清IgG抗体的四个主要重组 抗原先前提到的，和唾液伊加的GIAP和可溶性 将进行阿米巴抗原检测。 所有受试者将接受CMI研究 包括淋巴细胞胚细胞生成和γ测定 对丝裂原、可溶性阿米巴抗原和 4孔鉴定的重组E.溶组织抗原 初步 研究支持招募和遵循这一原则的高度可行性， 受试者数量。 考虑到已知的流行病感染率， 在德班地区，研究的规模已被确定为足够大 来回答所提出的问题。 这项提案将解决一个令人难以置信的 阿米巴病研究中的重要问题，并对疫苗产生重大影响 在该领域的发展和临床实践。

Entamoeba histolytic is an enteric protozoan that infects 10% of the world's population and is one of the following leading parasitic causes of death worldwide. Recently, a number of important amebic antigens have been isolated, characterized and cloned, including the 170kDa heavy subunit of the galactose-inhibitable adherence protein (GIAP), a 29kDa liver abscess-specific surface antigen, the major cysteine proteinase of E. histolytic, and a highly conserved 125kDa surface antigen. However, before work can proceed on development of an amebiasis vaccine we must gain a further understanding of natural immunity to this parasite. The overall objective of this proposal is to determine if natural immunity develops following invasive amebiasis and asymptomatic intestinal infection, and if so, to characterize the specific immune responses associated. They hypotheses to be tested are: 1) Cure of invasive amebiasis is followed by protective immunity against invasive amebiasis and asymptomatic intestinal infection with E. histolytic. 2) Elimination of asymptomatic pathogenic and nonpathogenic E. histolyatica intestinal infection is followed by immunity for months to years against recurrent infection; and 3) Immunity to invasive amebiasis is dependent on sustained antigen-specific cell mediated immune (CMI) responses, immunity to intestinal infection requires a similarly specific sIgA response. The specific aims of this proposal are to determine: 1) the incidence of invasive amebiasis and asymptomatic intestinal infection in seropositive individuals cured of amebic liver abscess and controls; 2) if there is an association between the amebic infection or disease; 3) the host immune response during asymptomatic E. histolytic infection and its relation to clearance of the infection; and 4) the incidence of recurrent asymptomatic infection, its correlation to host immune response, and whether immunity is strain specific. This will be accomplished by following 100 patients cured of amebic liver abscess and their 900 close associates for > 3 years at the Medical Research Council (Natal) and the King Edward VII Hospital in Durban, South Africa. Each of the 1000 subjects will have the follow-up every three months with determination of clinical status, occurrence of E. histolytic intestinal infection by culture and direct detection of fecal antigen and zymodeme analysis of infecting strain. In addition, assays of serum adherence protein antigenemia, serum IgG antibodies to each of the four major recombinant antigens previously mentioned, and salivary IgA to the GIAP and soluble amebic antigen will be performed. All subjects will have CMI studies consisting of lymphocyte blastogenesis and determination of gamma interferon production in response to mitogen, soluble amebic antigen and the 4 well characterized recombinant E. histolytic antigens. Preliminary studies support the high feasibility for enrolling and following this number of subjects. Considering known infection rates in the endemic area of Durban, the size of the study has been determined to be adequate to address the questions posed. This proposal will address an incredibly important issues in amebiasis research and have a major impact on vaccine development and clinical practice in the field.