DIMETHYLNITOSAMINE EFFECTS ON CELLULAR IMMUNITY

拟议的研究涉及中枢免疫抑制机制 由每日暴露于N-亚硝基二甲胺（DMN）产生。 已经 先前证明DMN对多种动物是有毒和致癌的， 动物种类。 这些作用似乎是由产生的代谢物介导的。 在DMN的酶促氧化由肝脏导致的形成 烷基化的核酸。 其他烷化剂，如环磷酰胺 已经被证明是有效的免疫抑制剂，不幸的是， 已经建立了暴露于DMN和改变之间的关系， 在免疫反应中。 初步结果显示， 由于巨噬细胞（M0）的变化， 功能 这一建议将确定DMN的抑制作用 在确定的功能测定中使用纯化的免疫活性细胞， 确定导致这种诱导的分子机制 变更。 概述的实验将确定每天暴露于 动物DMN损害T淋巴细胞，或M0群体的数量， 胞外酶谱，表型标记物的表达，以及在 细胞介导的反应 这些研究将包括重建T 淋巴细胞抗原和丝裂原反应;诱导迟发型 超敏反应和混合淋巴细胞反应，以及杀肿瘤试验。 DMN处理动物的骨髓将在集落刺激下生长 确定对M0体外生成影响的因子 使用以上概述的功能测定对群体进行测定。 的关系 细胞结构、DNA合成、细胞周期、胞外酶谱 并建立Ia抗原的表达。 虽然结果 提示血清或肝脏中存在免疫抑制成分 来自DMN处理动物的匀浆是可靠的，额外的实验 将确定直接接触DMN的影响。 另一个主要的推力 将是确定DMN诱导的介质（S）负责调制 M0成熟度 这将需要从肝匀浆中分离 和血清样品，然后使用已建立的 方法论。 这些研究还允许描绘 肝癌原DMN在分子上的免疫抑制性质， 以及这些有毒化合物如何损害免疫系统 响应能力。

The proposed research addresses the central immunosuppressive mechanism(s) generated by daily exposure to N-Nitroso-dimethylamine (DMN). It has been previously demonstrated that DMN is toxic and carcinogenic to a variety of animal species. The effects appear to be mediated by metabolites generated in the enzymatic oxidation of DMN by the liver resulting in the formation of alkylated nucleic acids. Other alkylating agents like cyclophosphamide have been shown to be potent immunosuppressants, few studies unfortunately have established the relationship between exposure to DMN and alterations in the immune response. Preliminary results have demonstrated a decrease in cell-mediated immunity as a result of changes in macrophage (M0) function. This proposal will determine the suppressive effects of DMN using purified immunocompetent cells in defined functional assays and identify the molecular mechanisms(s) responsible for this induced alteration. Experiments outlined will establish how daily exposure of animals to DMN compromises T-lymphocytes, or M0 populations in number, ectoenzyme profiles, expression of phenotypic markers, and function in cell-mediated responses. These studies will include reconstitution of T lymphocyte antigen and mitogen responses; induction of delayed typed hypersensitivity and mixed lymphocyte reactions, and tumorcidal assays. Bone marrow from DMN treated animals will be grown with colony stimulating factor to determine the effects on the in vitro generation of M0 populations using the above outlined functional assays. The relationship between the cellularity, DNA synthesis, cell-cycling, ectoenzyme profile and expression of Ia antigens will also be established. Although results suggest an immunosuppressive component(s) found on the serum or liver homogenates from DMN treated animals is responsible, additional experiments will establish the effects of direct DMN exposure. Another major thrust will be to identify the DMN induced mediator(s) responsible for modulation of M0 maturation. This will entail isolation from the liver homogenates and serum samples followed by biochemical analysis using established methodologies. These studies also permit delineation of the immunosuppressive nature of the hepatocarcinogen DMN at the molecular, cellular and animal level and how such toxic compounds compromise immune responsiveness.