Rivero-Lezcano Octavio M, Rodríguez-Aparicio Leandro B
Unit of Investigation, Hospital de León. Bldg. S. Antonio Abad. Altos de Nava s/n, 24008-León, Spain.
J Immunol Methods. 2008 Jul 20;336(1):16-21. doi: 10.1016/j.jim.2008.03.002. Epub 2008 Apr 3.
Antimicrobial activity in human monocytes infected with Mycobacterium tuberculosis has been difficult to demonstrate in vitro, and the molecular mechanisms allowing the bacteria to survive intracellularly are unknown. As a means to test the influence of bacterial products in the microbicidal activity of monocytes we have developed an infection model with Legionella pneumophila, which is killed by interferon gamma activated cells. We demonstrate that this model is useful because M. tuberculosis lysates inhibit one hundred fold the interferon gamma induced activity against L. pneumophila. Comparable degrees of inhibition are also detected when we use lysates from the less pathogenic Mycobacterium gordonae and the pathogenic Staphylococcus aureus, suggesting the participation of a common mechanism. This hypothesis is supported by the fact that the pattern of cytokine secretion is similar in all cases. A significant difference is, however, observed when we used lysates from the non-pathogenic Escherichia coli, which resulted in the recovery of low numbers of bacteria, probably because they induce the cell death of infected monocytes.
在体外很难证明感染结核分枝杆菌的人单核细胞具有抗菌活性，且细菌在细胞内存活的分子机制尚不清楚。作为一种测试细菌产物对单核细胞杀菌活性影响的方法，我们建立了一种嗜肺军团菌感染模型，该菌可被干扰素γ激活的细胞杀死。我们证明该模型是有用的，因为结核分枝杆菌裂解物可将干扰素γ诱导的针对嗜肺军团菌的活性抑制100倍。当我们使用致病性较低的戈登分枝杆菌和致病性金黄色葡萄球菌的裂解物时，也检测到了相当程度的抑制，这表明存在共同机制。这一假设得到了所有情况下细胞因子分泌模式相似这一事实的支持。然而，当我们使用非致病性大肠杆菌的裂解物时，观察到了显著差异，这导致细菌数量少量恢复，可能是因为它们诱导了被感染单核细胞的死亡。
