EFFECTS OF LEAD ON THE IMMUNE SYSTEM OF CHILDREN

拟议的研究涉及环境铅可能对 幼儿免疫系统的发育。 动物模型数据 系统表明铅是一种免疫抑制剂， 低于明显毒性所需的水平。 但是， 将这些数据外推到人类系统中。 一些城市儿童 年龄在1.5至6岁之间，血铅水平> 25 mug/100 ml 在密苏里州的格林县斯普林菲尔德地区发现了 通过参与当地WIC（妇女、婴儿和儿童）和铅 中毒预防方案。 这些方案的参与者是 目前需要定期验血，以及特殊的 咨询，以继续努力确定营养缺乏症， 以及铅的可能来源，并鼓励努力减少身体 负担 这群孩子，加上适当匹配的 在相同的筛选程序中确定的控制，提供了一个理想的 有机会调查血铅与 浓度和各种免疫学参数。 计划的试验， 评估B淋巴细胞的功能是血清IG浓度;特异性 破伤风类毒素、麻疹或脊髓灰质炎的抗体滴度;和B细胞计数。 确定T淋巴细胞功能的拟定测定法为T细胞计数; 辅助性T细胞/抑制性T细胞亚类;以及对有丝分裂原的反应。 吞噬 通过酵母细胞的单核细胞吞噬作用来测量功能。 的 这项研究具体目标如下： 1. 确定适当的样本量并设置控制， 实验组的数据进行统计分析后， 正常 各拟定试验的对照品。 2. 对初始样本和12个月样本进行筛选试验 跟随- 向上采样，以确定 免疫系统 对铅暴露敏感。 3. 评估筛选试验的数据，以确定 最 明确指出铅的有害影响， 处于扩张 研究和评估是否需要 纵向研究 本提案产生的数据将提供以下方面的宝贵信息： 在一个健康的人，体内铅暴露可能对健康造成的有害影响， 这类人群暴露的风险很大。 它将允许选择 免疫反应最敏感的方面， 最终测试 此外，后续样品的评价将 评估是否有必要就下列问题进行纵向研究： 慢性铅暴露对免疫系统发育的影响

The proposed study addresses the possible impact of environmental lead on the developing immune system of young children. Data from animal model systems indicate that lead is an immunosuppressive agent at levels far below those required for overt toxicity. But there are difficulties in extrapolating these data to human systems. A number of urban children between the ages of 1.5 to 6 years with blood lead levels >25 mug/100 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. Participants in these programs are presently required to have periodic blood tests, as well as special counseling in continuing attempts to identify nutritional deficiencies as well as possible sources of lead and to encourage efforts to reduce body burden. This group of children, together with appropriately matched controls identified during the same screening procedures, offer an ideal opportunity to investigate possible correlations between blood lead concentrations and various immunological parameters. Planned assays to assess function of B-lymphocytes are serum Ig concentrations; specific antibody titer vs. tetanus toxoid, measles, or polio; and B cell count. Proposed assays to determine T lymphocyte function are T cell count; ratio of T-helper/T-suppressor subclasses; and response to mitogens. Phagocytic function will be measured by monocyte phagocytosis of yeast cells. The specific aims of this study are as follow: 1. Determine appropriate sample size and set up control and experimental groups after statistical analysis of data from normal controls for each proposed assay. 2. Perform screening assays on an initial sample and 12-month follow- up sample to determine which component(s) of the immune system are sensitive to lead exposure. 3. Evaluate data from the screening assays to determine those most clearly indicating detrimental effects of lead for use in an expanded study and to assess the need for a longitudinal study. The data generated by this proposal will provide invaluable information on the possible detrimental health effects of in vivo lead exposure in a population at great risk for such exposure. It will allow selection of the most sensitive aspect of the immune response for further and more definitive testing. In addition, evaluation of the follow-up samples will assess the feasibility and need for a longitudinal study on effects of chronic lead exposure on the developing immune system.