Thüring H, Stenger S, Gmehling D, Röllinghoff M, Bogdan C
Institute for Clinical Microbiology and Immunology, University of Erlangen-Nürnberg, Germany.
Eur J Immunol. 1995 Dec;25(12):3229-34. doi: 10.1002/eji.1830251205.
Nitric oxide (NO) generated by the inducible isoform of nitric oxide synthase (iNOS) is implicated in a number of immunological processes including killing of intracellular parasites, suppression of T cell proliferation, production of cytokines and destruction of tissue in autoimmune diseases. Considering that cytokine-activated mouse macrophages, fibroblasts and endothelial cells are potent producers of NO, we investigated whether T cells, as central participants in immune responses, can also be activated for the release of NO. Neither thymocytes nor type 1 or type 2 T helper cell clones generated significant amounts of nitrite (the stable end product of NO in culture supernatants) when stimulated by T cell mitogens, cytokines or antigen in the presence of irradiated antigen-presenting cells. Similarly, T cells freshly isolated from mice acutely infected with the intracellular pathogen Leishmania major did not produce NO upon restimulation in vitro. The lack of NO production was not due to the expression of enzymatically inactive iNOS, as we were unable to detect any iNOS protein in activated T helper clones or in freshly isolated T cells from infected mice by Western (protein) blot analysis. Finally, we tested whether iNOS expression in T cells might be restricted to a minor subpopulation and therefore only detectable on a single cell level. After immunofluorescence staining of lymph node or spleen cells from infected mice with antibodies against iNOS, F4/80- or Thy-1-antigen, macrophages, but no T cells, were found to express iNOS. Thus, we have no evidence that activated T helper cell clones or T cells from L. major-infected mice are high producers of NO.
诱导型一氧化氮合酶（iNOS）产生的一氧化氮（NO）参与了许多免疫过程，包括杀伤细胞内寄生虫、抑制T细胞增殖、细胞因子的产生以及自身免疫性疾病中的组织破坏。鉴于细胞因子激活的小鼠巨噬细胞、成纤维细胞和内皮细胞是NO的有效产生者，我们研究了作为免疫反应核心参与者的T细胞是否也能被激活以释放NO。当在经辐射的抗原呈递细胞存在的情况下，用T细胞丝裂原、细胞因子或抗原刺激时，胸腺细胞、1型或2型辅助性T细胞克隆均未产生大量亚硝酸盐（培养上清液中NO的稳定终产物）。同样，从急性感染细胞内病原体利什曼原虫的小鼠中新鲜分离的T细胞在体外再次刺激时也不产生NO。NO产生的缺乏并非由于无酶活性的iNOS的表达，因为通过蛋白质印迹分析，我们在活化的辅助性T细胞克隆或来自感染小鼠的新鲜分离的T细胞中未能检测到任何iNOS蛋白。最后，我们测试了T细胞中iNOS的表达是否可能仅限于一小部分亚群，因此仅在单细胞水平上可检测到。在用抗iNOS、F4/80或Thy-1抗原的抗体对感染小鼠的淋巴结或脾细胞进行免疫荧光染色后，发现巨噬细胞而非T细胞表达iNOS。因此，我们没有证据表明活化的辅助性T细胞克隆或来自利什曼原虫感染小鼠的T细胞是NO的高产生产者。
