IMMUNITY IN CHILDREN WITH EXPOSURE TO ENVIRONMENTAL LEAD

拟议的研究涉及环境铅对环境的影响， 幼儿免疫系统的发展。在动物模型系统中，铅 发现远低于明显毒性所需的水平， 免疫抑制很难将这些数据外推到人类 系统.城市儿童（9个月至6岁）的研究人群 血液中的浓度大于10微克/100毫升， 密苏里州的斯普林菲尔德-格林县地区， 当地WIC（妇女、婴儿和儿童）和铅中毒预防 程序.这些孩子，以及来自 同样的计划，提供了一个理想的机会，开始一个 评估血铅浓度与 各种免疫系统参数。初步研究表明， 选择一些特定的试验，以评估可能的 铅对细胞数量的影响（WBC类型计数，包括分类 和淋巴细胞亚类）;对B细胞功能的影响（血清IG 浓度，包括IgE;细胞表面II类密度;细胞表面 活化抗原CD 71（转铁蛋白Rc）和B7的密度];影响 对T细胞功能（对IL-2的增殖反应;细胞表面密度 活化抗原CD 25（IL-2 Rc）、CD 71和CD 28）; 协调的免疫反应（疫苗的特异性抗体滴度; 对抗原的增殖反应;可溶性细胞因子受体的释放 (CD25和CD 27）;感染和过敏的频率）。初步 数据还允许确定适当的样本量， 生成这些选定参数的基本控制数据。 具体目标如下： 1.收集筛选试验数据，以达到30-35的样本量 每个对照组和实验组的儿童，年龄为9个月至6岁， 年龄 2.进行筛选试验，以确定免疫系统的哪些组分 系统对铅暴露敏感。 3.对选定的儿童进行纵向研究，为期12个月和24个月 后续样品。 4.最后对数据进行详尽的统计分析。 这项研究将提供关于一项 环境毒素对免疫系统的影响， exposure.此外，纵向研究将提供以下信息： 慢性铅暴露对免疫系统发育的影响。在 这一过程，幼儿正常免疫功能的知识， 增加

The proposed study addresses the impact of environmental lead on the developing immune system of young children. In animal model systems, lead levels far below those necessary for overt toxicity are found to be immunosuppressive. It is difficult to extrapolate these data to human systems. A study population of urban children (9 months to 6 years of age) with blood levels greater than 10 micrograms/1OO ml has been identified in the Springfield-Greene County area of Missouri through participation in local WIC (Women, Infants, and Children) and Lead Poisoning Prevention programs. This pool of children, with appropriately matched controls from the same programs, have offered an ideal opportunity to begin an assessment of possible correlations between blood lead concentrations and various immune system parameters. Preliminary studies have resulted in the selection of a number of specific assays proposed to assess possible effects of lead on cell numbers (counts of WBC types, including classes and subclasses of lymphocytes); effects on B cell function (serum Ig concentrations including IgE; cell surface class II density; cell surface density of the activation antigens CD71 (transferrin Rc) and B7]; effects on T cell function (proliferative response to IL-2; cell surface density of the activation antigens CD25 (IL-2 Rc), CD71, and CD28); and effects on concerted immune responses (specific antibody titers to vaccines; proliferative responses to antigens; release of soluble cytokine receptors (CD25 and CD27); frequencies of infections and allergies). Preliminary data have also allowed a determination of appropriate sample size and generation of essential control data for these selected parameters. Specific aims are as follow: 1. Gather data on screening assays to reach a sample size of 30-35 children per control and experimental group, age 9 months to 6 years of age. 2. Perform screening assays to determine which component(s) of the immune system are sensitive to lead exposure. 3. Conduct a longitudinal study of selected children, with 12 and 24 month follow-up samples. 4. Conclude with exhaustive statistical analysis of data. The study will provide invaluable information on the effects of an environmental toxin on the immune system in a population at great risk for exposure. In addition, the longitudinal study will provide information on the effects of chronic lead exposure on the developing immune system. In the process, knowledge of normal immune function in young children will be increased.