IMMUNE FUNCTION ASSAYS AS BIOMARKERS OF METAL EXPOSURE

这一部分的工作重点是确定免疫功能 检测可用作各种毒物暴露的生物标志物和 是否可以修改这些化验方法以检测特定的 毒药。八种不同的毒物被用来测试其适用性。 在这些检测中，有四种金属(汞、镉、铬酸盐和镍)和四种有机物 (苯二酚、对苯二酚、环氧苯乙烷和多氯联苯)。 使用B细胞和T细胞有丝分裂原检测来评估适用性 混合淋巴细胞培养(MLC)，T细胞检测。剂量/反应 所有八种毒物都在体外暴露，使用 浓度跨越五个数量级(100ppm-10ppb)。 在测试的最低浓度(10 Ppb)下，所有的毒物都会引起 至少一种检测方法的变化和所有金属引起的AT变化 至少两次化验。此外，在10 ppb时，所有的金属都增强了 MLC中T细胞的增殖情况。因为成功地使用了 这些剂量/反应研究中的金属，我们的下一系列实验 专注于修改这些增殖试验以检测体内暴露 关于特定的金属和理解金属改变的机制 淋巴细胞增殖。在这些研究中，我们使用了暴露在 活体对铬酸盐或镉的反应。使用有丝分裂原的变种和 MLC检测显示，从染铬大鼠分离的细胞 与从镉暴露的大鼠分离的细胞不同。此外，在 体内镉暴露而不是体内铬酸盐暴露增加了 暴露大鼠脾细胞对同种异体脾细胞的抗原性 脾细胞。我们的结果表明，这些增殖的变种 化验可能有助于检测低水平接触铬酸盐或 镉，也许还有其他金属。在即将到来的授权期内，我们 将专注于应用这些化验(包括原始化验和我们的 变种)对暴露于铬酸盐和镉的人类。此外，我们 将继续调查这些化验的变种如何使用 作为各种金属暴露的生物标志物。我们还将 克隆人和动物的金属反应T细胞的尝试 暴露在铬酸盐和镉中。用镍已经做到了这一点-- 接触过的个体，我们有证据表明铬酸盐，也许还有其他 金属，诱导金属反应性T细胞亚群。该不该 克隆实验将会成功，它将是一个强大的生物标志物 金属暴露的可能性。

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.