DIMETHYLNITOSAMINE EFFECTS ON CELLULAR IMMUNITY

拟议的研究涉及中枢免疫抑制机制(S) 因每天接触N-亚硝基二甲胺(DMN)而产生。一直以来 此前已证明，DMN对多种化合物具有毒性和致癌作用 动物物种。这种影响似乎是由产生的代谢物介导的。 在肝脏对DMN的酶催化氧化过程中形成 烷基化核酸。其他烷基化试剂，如环磷酰胺 已经被证明是有效的免疫抑制药，不幸的是，很少有研究 已经确定了接触DMN和改变之间的关系 在免疫反应中。初步结果显示， 巨噬细胞(M0)变化引起的细胞免疫 功能。这一提议将决定DMN的抑制效果 在确定的功能分析中使用纯化的免疫活性细胞和 确定导致这种情况的分子机制(S) 更改。概述的实验将确定每日暴露于 动物对DMN的反应损害了T淋巴细胞或M0群体的数量， 胞外酶谱、表型标志物的表达和功能 细胞介导的反应。这些研究将包括T的重建 淋巴细胞抗原和有丝分裂原反应.延迟型诱导 超敏反应和混合淋巴细胞反应，以及杀瘤试验。 DMN处理的动物的骨髓将在集落刺激下生长 影响M0细胞体外生成的因素 使用上述功能检测的人群。两国关系 在细胞密度、DNA合成、细胞周期、胞外酶之间 也将建立Ia抗原的表达。虽然结果 提示在血清或肝脏中发现的免疫抑制成分(S) DMN处理的动物的匀浆是有责任的，额外的实验 将确定直接接触DMN的影响。另一个主要推力 将确定DMN诱导的调节剂(S)负责调制 M0成熟度。这将需要从肝脏匀浆中分离出来。 以及随后使用已建立的生化分析的血清样本 方法论。这些研究还可以描绘出 肝癌致癌物DMN在分子水平上的免疫抑制性质， 细胞和动物水平以及这些有毒化合物如何损害免疫 响应性。

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.