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IMMUNODOMINANT TARGETS OF CMI TO CRYPTOSPORIDIUM

CMI 对隐孢子虫的免疫显性靶点

基本信息

批准号：
7585748
负责人：
JAN R MEAD
金额：
$ 21.01万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1996
资助国家：
美国
起止时间：
1996-05-01 至 2012-03-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Cryptosporidium parvum infections in immunocompromised individuals often develop into chronic, severe cryptosporidiosis that can become life-threatening. In conjunction with low CD4+ cell levels, insufficiency of other immune system factors are expected to contribute to infection chronicity in the immunodeficient host. In contrast, cytokines such as gamma interferon (IFN-gamma) have been implicated in control of infection in both adults and children. Elucidation of immune responses and identification of features of immune dysregulation, such as cytokine abnormalities or inability of T-cells to proliferate in response to key cryptosporidial antigens, might identify patients at high risk for cryptosporidiosis. It is hypothesized that infection resolution in the immunocompetent host is linked to specific antigens responsible for the activation of lymphocyte populations and induction of cytokines and allows for protection from subsequent infections. Consequently, a lack of response to these key antigens and development of certain cytokine profiles may lead to chronic, intractable infections and limited, if any, protective responses. We have recently developed a model useful for evaluating protective immunity to C. parvum infection in adult experimental animals. This model, which uses IL-12 deficient or "knockout" mice, is an important advance as previous tools were inadequate to effectively assess immunity. We now plan to use this model to determine the cell types and cytokines necessary for the generation and maintenance of protective immune responses. The necessity of subpopulation of lymphocytes will be determined by depletion of specific cell populations (e.g. CD4+, CD8+, and IEL cells) as well as key cytokines (IFN-gamma, IL-15 and IL-4) during primary and challenge infection of IL-12 knockout mice. To determine if protective responses identified by these experiments can be induced through immunization, immunodominant antigens (Cp40, Cp23, Cp17, Cp15, CpPO, CpP1, and CpP2) will be evaluated to determine if they can generate protective responses in our mouse vaccine model. This will be accomplished by immunizing mice with a DNA construct of these antigens, assessing their ability to elicit immune responses, and challenging mice with C. parvum to determine the degree of protection achieved.

描述（由申请人提供）：免疫功能低下个体的微小隐孢子虫感染通常发展为慢性、严重的隐孢子虫病，可危及生命。与低CD 4+细胞水平相结合，其他免疫系统因子的不足预计会导致免疫缺陷宿主的感染慢性化。相比之下，细胞因子如γ干扰素（IFN-γ）已涉及控制成人和儿童的感染。阐明免疫反应和识别免疫失调的特征，如细胞因子异常或T细胞无法增殖以响应关键的隐孢子虫抗原，可能会识别隐孢子虫病的高风险患者。假设免疫活性宿主中的感染消退与负责淋巴细胞群活化和细胞因子诱导的特异性抗原相关，并允许保护免受后续感染。因此，缺乏对这些关键抗原的反应和某些细胞因子谱的发展可能导致慢性、难治性感染和有限的保护性反应（如果有的话）。我们最近开发了一个模型，用于评估保护性免疫C。成年实验动物的细小病毒感染。这种使用IL-12缺陷或“敲除”小鼠的模型是一个重要的进步，因为以前的工具不足以有效评估免疫力。我们现在计划使用该模型来确定保护性免疫应答的产生和维持所需的细胞类型和细胞因子。淋巴细胞亚群的必要性将通过在IL-12敲除小鼠的初次和攻击感染期间特定细胞群（例如，CD 4+、CD 8+和IEL细胞）以及关键细胞因子（IFN-γ、IL-15和IL-4）的消耗来确定。为了确定通过这些实验鉴定的保护性应答是否可以通过免疫诱导，将评价免疫显性抗原（Cp 40、Cp 23、Cp 17、Cp 15、CpPO、CpP 1和CpP 2），以确定它们是否可以在我们的小鼠疫苗模型中产生保护性应答。这将通过用这些抗原的DNA构建体免疫小鼠，评估它们引发免疫应答的能力，并用C.以确定达到的保护程度。