IMMUNODOMINANT TARGETS OF CMI TO CRYPTOSPORIDIUM

描述(申请人提供)：免疫受损患者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。与低水平的CD4+细胞一起，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，如干扰素(干扰素)，被认为与成人和儿童的感染控制有关。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细胞对关键隐孢子虫抗原的反应不能增殖，可能会识别出隐孢子虫病的高危患者。假设具有免疫能力的宿主中的感染分解与负责激活淋巴细胞群体和诱导细胞因子的特定抗原有关，并允许保护其免受后续感染。因此，缺乏对这些关键抗原的反应和某些细胞因子谱的形成可能会导致慢性、难治性感染和有限的保护性反应。我们最近开发了一种模型，可用于评估成年实验动物对微小弧菌感染的保护性免疫。该模型使用了IL-12缺陷或“基因敲除”的小鼠，是一个重要的进步，因为以前的工具不足以有效地评估免疫力。我们现在计划使用这个模型来确定产生和维持保护性免疫反应所需的细胞类型和细胞因子。淋巴细胞亚群的必要性将取决于在IL-12基因敲除小鼠的初次和挑战感染过程中特定细胞群(如CD4+、CD8+和IEL细胞)以及关键细胞因子(干扰素-γ、IL-15和IL-4)的耗竭。为了确定这些实验确定的保护性反应是否可以通过免疫诱导，将对免疫优势抗原(Cp40、Cp23、Cp17、Cp15、CpPO、CpP1和CpP2)进行评估，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反应。这将通过用这些抗原的DNA结构免疫小鼠，评估它们引发免疫反应的能力，并用微小弧菌攻击小鼠来确定达到的保护程度来实现这一点。

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.