IMMEDIATE HYPERSENSITIVITY RESPONSES--CONTROL IN PARASITIC HELMINTH INFECTIONS

立即超敏反应——控制寄生虫感染

• 批准号: 6288989
• 负责人: THOMAS B NUTMAN
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6288989
• 关键词: cytokine; enzyme linked immunosorbent assay; eosinophil; flow cytometry; helminthiasis; helminthic antigen; host organism interaction; human tissue; immediate hypersensitivity; immunoglobulin E; immunoglobulin G; immunoregulation; inflammation

Using anthelminthic treatment-induced eosinophilia (in both lymphatic filariasis and onchocerciasis) as a model for physiological activation and recruitment of eosinophils, we have clearly established that there is an inverse relationship between circulating levels of RANTES and the ability of eosinophils to migrate from the blood to the sites of inflammation. Using immunohistochemical staining of skin biopsies taken from patients with onchocerciasis after ivermectin therapy, we have shown that, once recruited, the eosinophils degranulate and stimulate eotaxin production thereby allowing further eosinophil accumulation. In a separate study in India where a flow cytometer is available, we have examined the kinetics of eosinophil activation following definitive antifilarial therapy. The data show that there is marked upregulation of the integrins (VLA-4, CD44 and alpha4beta7) as well as CD23 within the first 24 hours. IL-5 levels peaked soon thereafter and predated the universal eosinophilia that occurred following therapy.One other major approach taken to understand eosinophil activation and regulation is a genetic approach in which we have identified a large kindred with familial hypereosinophilia. This syndrome is autosomal dominant and has allowed physical linkage of the responsible gene to chromosome 5 near to marker D5S1505. There are a number of genes in the area, including that for interleukin 5, but subsequent complete sequencing of the IL-5, IL-3 and GM-CSF gene and their promotes has not identified the candidate gene or mutation. Over the past year an integrated approach to this disorder has been taken by studying close to 17 members of the kindred. Data collected on their cells and eosinophils have suggested that their eosinophils are without major activation phenotypes (based on cell surface marker expression, electron microscopy, eosinophil survival assays). Two other candidate genes have been identified but await full sequencing. Using differential representational analysis of normal and activated eosinophils close to 65 activation-specific gene products have been identified. Each is being examined for differential expression in a variety of in vitro systems.Because IgE and IgG4 levels are increased in helminth infection, the mechanisms underlying these increases have been examined, initially using a model of parasite antigen-driven in vitro production of antibody. Having identified recombinant antigens capable of inducing isotype switching to IgG4/IgE, the ability of these antigens to drive B cells in the absence of T cells was shown to occur, providing anti-CD40 and the appropriate cytokine milieu was provided. Further, these same antigens have been shown capable of priming T cells from naive hosts in such a way that they (in presence of these recombinant antigens) induce B cells to differentiate into B cells capable of producing antigen-specific IgE and IgG4. Moreover, germline expression of IgE and IgG4 in acute helminth infections has now been shown and suggests a mechanism by which parasite antigen specifically induce switching to these important isotypes. - Hypereosinophilia, allergy, immediate hypersensitivity, helminth, filarial infections, cytokines, IgE - Human Subjects

使用驱虫药治疗引起的嗜酸性粒细胞增多症(淋巴丝虫病和盘尾丝虫病)作为嗜酸性粒细胞生理激活和募集的模型，我们清楚地确定了循环中RANTES水平和嗜酸性粒细胞从血液迁移到炎症部位的能力之间存在负相关关系。通过对伊维菌素治疗后的盘尾丝虫病患者皮肤活检的免疫组织化学染色，我们发现，一旦被招募，嗜酸性粒细胞脱颗粒并刺激嗜酸性粒细胞的产生，从而允许进一步的嗜酸性粒细胞聚集。在印度的一项单独的研究中，我们使用了流式细胞仪，检测了明确的抗丝虫病治疗后嗜酸性粒细胞激活的动力学。数据显示，在最初的24小时内，整合素(VLA-4、CD44和α4β7)以及CD23明显上调。IL-5水平在治疗后不久达到峰值，并早于治疗后发生的普遍嗜酸性粒细胞增多。另一种了解嗜酸性粒细胞激活和调节的主要方法是遗传学方法，在这种方法中，我们发现了一个患有家族性高嗜酸粒细胞症的大家族。这种综合征是常染色体显性遗传，并允许将相关基因物理连锁到标记D5S1505附近的5号染色体上。该区域有许多基因，包括白介素5的基因，但随后对IL-5、IL-3和GM-CSF基因及其启动子的完整测序尚未确定候选基因或突变。在过去的一年里，对这种疾病采取了一种综合的方法，研究了近17名亲属。收集的细胞和嗜酸性粒细胞的数据表明，他们的嗜酸性粒细胞没有主要的激活表型(基于细胞表面标记表达，电子显微镜，嗜酸性粒细胞存活分析)。另外两个候选基因已经被确定，但正在等待完整的测序。利用对正常和激活的嗜酸性粒细胞的不同代表性分析，已鉴定出近65种激活特异性基因产物。由于寄生虫感染时IgE和IgG4水平升高，因此研究了这些升高背后的机制，最初使用的是寄生虫抗原驱动的体外抗体产生模型。在鉴定出能够诱导同型转换为IgG4/IgE的重组抗原后，在没有T细胞的情况下，这些抗原能够在提供抗CD40和适当的细胞因子环境的情况下驱动B细胞。此外，这些相同的抗原已经被证明能够启动来自幼稚宿主的T细胞，在这些重组抗原存在的情况下，它们诱导B细胞分化为能够产生抗原特异性IgE和IgG4的B细胞。此外，在急性蠕虫感染中，IgE和IgG4的种系表达已经被证明，并提示了一种机制，通过这种机制，寄生虫抗原特异性地诱导转换到这些重要的亚型。-嗜酸性粒细胞增多症、过敏、即刻超敏、蠕虫、丝虫感染、细胞因子、免疫球蛋白E-人类受试者