TNF-α controls intracellular mycobacterial growth by both inducible nitric oxide synthase-dependent and inducible nitric oxide synthase-independent pathways
TNF-α controls intracellular mycobacterial growth by both inducible nitric oxide synthase-dependent and inducible nitric oxide synthase-independent pathways
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DOI：
10.4049/jimmunol.166.11.6728
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发表时间：
2001-06-01
影响因子：
4.4
通讯作者：
Kaplan, G
中科院分区：
文献类型：
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作者：
Bekker, LG;Freeman, S;Kaplan, G
在体外研究了TNF-α在小鼠巨噬细胞中控制分枝杆菌生长中的作用。用仅表达载体（BCG-载体）的重组牛分枝杆菌卡介苗（BCG）感染来自TNF-α基因破坏（TNF-敲除（KO））小鼠的巨噬细胞导致细胞内杆菌的对数生长。用BCG分泌的鼠TNF-α（BCG-TNF）感染导致细菌杀伤。BCG-TNF的杀伤作用与诱导型NO合酶（iNOS）蛋白的快速积累和亚硝酸盐的产生有关。BCG载体的不受控制的生长与低iNOS表达相关，但不产生亚硝酸盐。因此，iNOS表达似乎是TNF-α独立的，但NO的iNOS产生需要TNF-α。在用BCG-TNF感染的TNF-KO巨噬细胞培养物中，氨基胍（AMG）抑制iNOS可消除对杆菌的杀伤。然而，生物体的生长仍然受到抑制，表明iNOS非依赖性TNF-α介导的生长抑制。为了证实这一点，用BCG载体或BCG-TNF感染来自iNOS-KO小鼠的巨噬细胞。正如预期，在培养基中未检测到亚硝酸盐。TNF-α仅在BCG-TNF感染后才被检测到。在iNOS-KO巨噬细胞中，BCG的生长仅在BCG-TNF感染中被抑制。这些结果表明，在缺乏iNOS活性的情况下，TNF-α刺激巨噬细胞以控制细胞内BCG的生长。因此，似乎存在TNF-α依赖性-iNOS依赖性杀伤途径以及TNF-α依赖性-iNOS非依赖性生长抑制途径，用于控制鼠巨噬细胞中的细胞内分枝杆菌。免疫学杂志2001，166：6728-6734.
The role of TNF-a in the control of mycobacterial growth in murine macrophages was studied in vitro. Infection of macrophages from TNF-a gene disrupted (TNF-knockout (KO)) mice with recombinant Mycobacterium bovis bacillus Calmette Guerin (BCG) expressing the vector only (BCG-vector) resulted in logarithmic growth of the intracellular bacilli. Infection with BCG-secreting murine TNF-a (BCG-TNF) led to bacillary killing. Killing of BCG-TNF was associated with rapid accumulation of inducible NO synthase (iNOS) protein and the production of nitrite. The uncontrolled growth of BCG-vector was associated with low iNOS expression but no nitrite production. Thus, iNOS expression appears to be TNF-a independent but iNOS generation of NO requires TNF-a. In cultures of TNF-KO macrophages infected with BCG-TNF, inhibition of iNOS by aminoguanidine (AMG) abolished the killing of the bacilli. However, the growth of the organisms was still inhibited, suggesting an iNOS-independent TNF-alpha -mediated growth inhibition. To confirm this, macrophages from iNOS-KO mice were infected with either BCG-vector or BCG-TNF. As expected, no nitrite was detected in the culture medium. TNF-a was detected only when the cells were infected with BCG-TNF. In the iNOS-KO macrophages, the growth of BCG was inhibited only in the BCG-TNF infection. These results suggest that in the absence of iNOS activity, TNF-a stimulates macrophages to control the growth of intracellular BCG. Thus, there appears to be both a TNF-alpha -dependent-iNOS-dependent killing pathway as well as a TNF-alpha- dependent-iNOS-independent growth inhibitory pathway for the control of intracellular mycobacteria in murine macrophages. The Journal of immunology 2001,166:6728-6734.