Moisan J, Wojciechowski W, Guilbault C, Lachance C, Di Marco S, Skamene E, Matlashewski G, Radzioch D
Department of Experimental Medicine, McGill University, and Montreal General Hospital Research Institute, Montreal, Quebec, Canada.
Antimicrob Agents Chemother. 2001 Nov;45(11):3059-64. doi: 10.1128/AAC.45.11.3059-3064.2001.
The mouse bcg host resistance gene is known to control the activation of host macrophages for killing of intracellular parasites like Leishmania donovani as well as intracellular bacteria, including Mycobacterium bovis BCG and Salmonella enterica serovar Typhimurium. The Nramp1 gene has been mapped to this locus and affects the efficiency of macrophage activation. It has been shown that imidazoquinoline compounds, including S28463, are able to improve the clearance of a number of intracellular pathogens such as herpes simplex virus 2, human papillomavirus, and Leishmania. The goal of this study was to determine whether S28463 is efficient against infection with another intracellular pathogen, M. bovis BCG, and to determine the molecular basis underlying this effect. To achieve this, B10A.Nramp1(r) and B10A.Nramp1(-/-) mice were infected with M. bovis BCG and treated with S28463. The bacterial content in the spleen from these mice was assayed by a colony-forming assay. In addition, in vitro experiments were performed using bone marrow-derived macrophage cell lines from these mice. These cells were treated with S28463 and/or gamma interferon (IFN-gamma), and nitric oxide (NO) production was measured. Our study was able to show that S28463 acts in synergy with IFN-gamma to increase the production of NO in vitro. We were also able to demonstrate that mice that carried the resistant allele of the Nramp1 gene and were infected with M. bovis BCG responded to treatment with S28463, resulting in a decreased bacterial load after 2 weeks of treatment. Mice that do not express the Nramp1 gene responded only to a very large dose of S28463, and the response was not as efficient as that observed in mice carrying a wild-type Nramp1 allele. Our data provide evidence for the potential of S28463 as an immunomodulator that may be helpful in designing efficient strategies to improve host defense against mycobacterial infection.
已知小鼠卡介苗宿主抗性基因可控制宿主巨噬细胞的激活，以杀死细胞内寄生虫，如杜氏利什曼原虫，以及细胞内细菌，包括牛分枝杆菌卡介苗和鼠伤寒沙门氏菌。Nramp1基因已被定位到该位点，并影响巨噬细胞激活的效率。已表明，包括S28463在内的咪唑喹啉化合物能够提高对多种细胞内病原体的清除率，如单纯疱疹病毒2型、人乳头瘤病毒和利什曼原虫。本研究的目的是确定S28463对另一种细胞内病原体牛分枝杆菌卡介苗感染是否有效，并确定这种作用的分子基础。为实现这一目标，将B10A.Nramp1(r)和B10A.Nramp1(-/-)小鼠感染牛分枝杆菌卡介苗并用S28463进行治疗。通过菌落形成试验测定这些小鼠脾脏中的细菌含量。此外，使用来自这些小鼠的骨髓源性巨噬细胞系进行体外实验。用S28463和/或γ干扰素（IFN-γ）处理这些细胞，并测量一氧化氮（NO）的产生。我们的研究能够表明，S28463与IFN-γ协同作用，在体外增加NO的产生。我们还能够证明，携带Nramp1基因抗性等位基因并感染牛分枝杆菌卡介苗的小鼠对S28463治疗有反应，治疗2周后细菌载量降低。不表达Nramp1基因的小鼠仅对非常大剂量的S28463有反应，且反应不如携带野生型Nramp1等位基因的小鼠有效。我们的数据为S28463作为一种免疫调节剂的潜力提供了证据，这可能有助于设计有效的策略来改善宿主对分枝杆菌感染的防御。
