IMMUNE FUNCTION ASSAYS AS BIOMARKERS OF METAL EXPOSURE

这项工作的重点是确定免疫功能是否 测定可用作各种毒物暴露的生物标志物， 是否可以修改这些测定以检测特定 有毒物质 用8种不同的毒物进行了适用性试验 在这些分析中，四种金属（Hg、Cd、铬酸盐和Ni）和四种有机物 （苯醌、氢醌、氧化苯乙烯和芳氯（一种PCB））。 使用B细胞和T细胞有丝分裂原测定评估适用性， 混合淋巴细胞培养（MLC），一种T细胞测定。 剂量/反应 在体外对所有八种毒物进行了暴露， 浓度跨越五个数量级（100 ppm - 10 ppb）。 在测试的最低浓度（10 ppb）下，所有毒物均诱导 至少一项试验中的变化和所有金属诱导的at 至少两次测试。 此外，在10 ppb下，所有金属都增强了 MLC中T细胞的增殖。 由于 在这些剂量/反应研究中，我们的下一系列实验 重点是修改这些增殖试验，以检测体内暴露 具体金属和了解机制，使金属改变 淋巴细胞增殖 在这些研究中，我们使用了暴露在 体内的铬酸盐或镉。 使用有丝分裂原的变体， MLC检测，从暴露于铬酸盐的大鼠中分离的细胞对 与从暴露于镉的大鼠中分离的细胞不同。 而且在 体内镉暴露而不是体内铬酸盐暴露增强了 从暴露大鼠中采集的脾细胞对同种异体的抗原性 脾细胞 我们的研究结果表明，这些增殖的变体 测定法可用于检测低水平暴露于铬酸盐或铬酸盐 镉和其他金属。 在接下来的时间里，我们 我将专注于应用这些检测（包括原始检测和我们的 变种）暴露于铬酸盐和镉的人类。 另外我们 将继续研究如何使用这些检测方法的变体 作为暴露于多种金属的生物标志物。 我们还将 试图从人类和动物身上克隆金属反应T细胞 暴露在铬酸盐和镉中 这已经用镍做过了- 我们有证据表明，铬酸盐，也许其他 金属，诱导金属应答性T细胞亚群。 如果 如果克隆实验成功， 金属暴露。

Work in this component has focused on determining whether immune-function assays can be used as biomarkers of exposure for a variety of toxicants and whether these assays can be modified to detect exposure to specific toxicants. Eight different toxicants were used to test the applicability of these assays, four metals (Hg, Cd, chromate and Ni) and four organics (benzoquinone, hydroquinone, styrene oxide and aroclor, a PCB). Applicability was assessed using both B-cell and T-cell mitogen assays and the mixed lymphocyte culture (MLC), a T-cell assay. Dose/response exposures were conducted in vitro with all eight toxicants using concentrations that spanned five orders of magnitude (100 ppm - 10 ppb). At the lowest concentration tested (10 ppb), all of the toxicants induced changes in at least one assay and all of the metals induced changes in at least two assays. Moreover at 10 ppb, all of the metals enhanced the proliferation of T-cells in the MLC. Because of the success with the metals in these dose/response studies, our next series of experiments focused on modifying these proliferation assays to detect in vivo exposures to specific metals and on understanding the mechanisms whereby metals alter lymphocyte proliferation. For these studies we employed rats exposed in vivo to either chromate or to cadmium. Using variants of the mitogen and MLC assays, cells isolated from rats exposed to chromate responded differently than cells isolated from rats exposed to cadmium. Moreover, in vivo cadmium exposure but not in vivo chromate exposure enhanced the antigenicity of splenocytes taken from exposed rats toward allogeneic splenocytes. Our results indicate that variants of these proliferation assays may be useful for detecting low-level exposures to chromate or cadmium and perhaps other metals as well. In the coming grant period we will focus on applying these assays (both the original assays and our variants) to humans exposed to chromate and to cadmium. In addition, we will continue investigations into how variants of these assays can be used as biomarkers of exposure for a wide variety of metals. We will also attempt to clone metal-responsive T-cells from both humans and animals exposed to chromate and cadmium. This has already been done with nickel- exposed individuals and we have evidence that chromate, and perhaps other metals, induce a subpopulation of metal responsive T-cells. Should the cloning experiments be successful, it would represent a powerful biomarker of metal exposure.