Rich E A, Torres M, Sada E, Finegan C K, Hamilton B D, Toossi Z
Department of Medicine, Case Western Reserve University, Cleveland, OH 44106-4984, USA.
Tuber Lung Dis. 1997;78(5-6):247-55. doi: 10.1016/s0962-8479(97)90005-8.
Although nitric oxide (NO) is a major proximate mediator of microbicidal activity in murine macrophages against intracellular pathogens including mycobacteria, its production by and effector role in human macrophages is not clear.
To determine the capacity of Mycobacterium tuberculosis (MTB) to stimulate NO in human monocytes (MN) and alveolar macrophages (AM) and to assess the relationship between NO production and intracellular growth of MTB.
NO production (measured as nitrite) by MTB (H37Ra)-infected macrophages and intracellular growth of MTB were measured in cells from 17 healthy subjects.
MTB (5:1, MTB:cells) stimulated little to no NO by MN, but induced NO in AM at days 4 and 7 after infection. There was, however, variability in the response by AM to MTB: among seven subjects MTB-induced NO was low (4 +/- 2 microM, mean +/- SE); six subjects were moderate (56 +/- 11); four subjects were high (502 +/- 167). NO synthase inhibitors inhibited the production of NO by AM but did not significantly affect the intracellular growth of MTB, although a trend towards increased intracellular growth was seen on day 4 of culture. Intracellular growth of MTB in AM from low NO producers was significantly higher than that in AM from moderate NO producers, P < or = 0.05. Inducible NO synthase (iNOS) mRNA by RT-PCR was constitutively expressed by both MN and AM, but was further stimulated by MTB in AM > MN; MTB-induced iNOS protein was present in both MN and AM by Western blot analysis.
Thus, MTB-infected human AM are capable of producing NO and NO production correlates with intracellular growth inhibition of MTB in AM suggesting that NO may serve either directly or indirectly as a mycobactericidal mediator in human tissue macrophages.
尽管一氧化氮（NO）是小鼠巨噬细胞针对包括分枝杆菌在内的细胞内病原体的杀菌活性的主要近端介质，但其在人类巨噬细胞中的产生及其效应作用尚不清楚。
确定结核分枝杆菌（MTB）刺激人类单核细胞（MN）和肺泡巨噬细胞（AM）产生NO的能力，并评估NO产生与MTB细胞内生长之间的关系。
在17名健康受试者的细胞中测量MTB（H37Ra）感染的巨噬细胞产生的NO（以亚硝酸盐衡量）以及MTB的细胞内生长情况。
MTB（5:1，MTB:细胞）刺激MN产生的NO很少或几乎没有，但在感染后第4天和第7天诱导AM产生NO。然而，AM对MTB的反应存在差异：在7名受试者中，MTB诱导的NO较低（4±2微摩尔，平均值±标准误）；6名受试者为中等水平（56±11）；4名受试者较高（502±167）。NO合酶抑制剂抑制了AM产生NO，但对MTB的细胞内生长没有显著影响，尽管在培养第4天观察到细胞内生长有增加的趋势。低NO产生者的AM中MTB的细胞内生长显著高于中等NO产生者的AM，P≤0.05。通过逆转录聚合酶链反应（RT-PCR）检测，诱导型NO合酶（iNOS）mRNA在MN和AM中均有组成性表达，但MTB对AM的刺激作用大于MN；通过蛋白质印迹分析，MTB诱导的iNOS蛋白在MN和AM中均存在。
因此，MTB感染的人类AM能够产生NO且NO产生与AM中MTB的细胞内生长抑制相关，这表明NO可能直接或间接作为人类组织巨噬细胞中的杀菌介质。
