Singh Prati Pal, Goyal Amit
Centre of Infectious Diseases, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, S. A. S. Nagar, 160 062 Punjab, India.
Springerplus. 2013 Dec 21;2:686. doi: 10.1186/2193-1801-2-686.
Human tuberculosis (TB), a chronic inflammatory disease is caused by Mycobacterium tuberculosis, a facultative intramacrophage pathogen. The highly complex interactions between mycobacteria and macrophages (MΦs), characterized in part by the induction and elaboration of several cytokines including IL-1, IL-6, IL-10, IL-12 p40 and IL-12 p70 are not yet fully understood. The cytokines are known to have important bearing on the pathogenesis and host defense during TB. We thus studied different patterns of cytokines elaborated by mouse peritoneal macrophages (PMs) following their interaction with live and heat-killed, virulent and avirulent, and pathogenic and non-pathogenic mycobacteria, in vitro.
Pathogenic M. tuberculosis H37Rv (virulent) and M. tuberculosis H37Ra (avirulent), and non-pathogenic M. smegmatis were grown in complete Middle Brook 7H9 broth. For some experiments, mycobacteria were heat-killed (80°C; 20 min). The supernatants of cultured PMs, having ingested mycobacteria for 6 h, 24 h, 4 days and 7 days, were harvested for the quantification of IL-1, IL-6, IL-10, IL-12 p40 and IL-12 p70 by using a multiplex suspension cytokine array system.
The PMs infected with heat-killed mycobacteria, as compared to their respective live counterparts, invariably elaborated significantly (p < 0.001) increased (approximately 2-3-fold) amounts of IL-6, at all the time-points studied, in vitro. Further, PMs infected with M. tuberculosis H37Ra, as compared to M. tuberculosis H37Rv, elaborated 4-5-fold more (p < 0.001) IL-6. Non-pathogenic M. smegmatis, as compared to pathogenic M. tuberculosis H37Ra and M. tuberculosis H37Rv, following infection, induced the PMs to elaborate highest (p < 0.001) amounts of IL-6 at all the time-points studied. Curiously, none of these mycobacteria-infected PMs elaborated IL-1, IL-10, IL-12 p40 and IL-12 p70, significantly.
IL-6 appears to be the only major cytokine elaborated by mycobacteria-infected PMs, in vitro, and thus may function as a potent biomarker of mycobacterial infection, either stand-alone or along with other cytokines.
人类结核病是一种由结核分枝杆菌引起的慢性炎症性疾病，结核分枝杆菌是一种兼性巨噬细胞内病原体。分枝杆菌与巨噬细胞（MΦs）之间高度复杂的相互作用，部分特征是诱导和产生包括白细胞介素-1（IL-1）、白细胞介素-6（IL-6）、白细胞介素-10（IL-10）、白细胞介素-12 p40和白细胞介素-12 p70在内的多种细胞因子，但尚未完全了解。已知这些细胞因子在结核病的发病机制和宿主防御中具有重要作用。因此，我们在体外研究了小鼠腹腔巨噬细胞（PMs）与活的和热灭活的、有毒力和无毒力的、致病性和非致病性分枝杆菌相互作用后产生的不同细胞因子模式。
致病性结核分枝杆菌H37Rv（有毒力）和结核分枝杆菌H37Ra（无毒力），以及非致病性耻垢分枝杆菌在完全的Middle Brook 7H9肉汤中培养。对于一些实验，分枝杆菌经热灭活（80°C；20分钟）。培养6小时、24小时、4天和7天摄入分枝杆菌的PMs的上清液被收集，使用多重悬浮细胞因子阵列系统定量IL-1、IL-6、IL-10、IL-12 p40和IL-12 p70。
与各自的活分枝杆菌相比，感染热灭活分枝杆菌的PMs在体外所有研究的时间点均始终显著（p < 0.001）增加（约2 - 3倍）IL-6的产生量。此外，与结核分枝杆菌H37Rv相比，感染结核分枝杆菌H37Ra的PMs产生的IL-6多4 - 5倍（p < 0.001）。与致病性结核分枝杆菌H37Ra和结核分枝杆菌H37Rv相比，感染后非致病性耻垢分枝杆菌在所有研究的时间点诱导PMs产生的IL-6量最高（p < 0.001）。奇怪的是，这些感染分枝杆菌的PMs均未显著产生IL-1、IL-10、IL-12 p40和IL-12 p70。
IL-6似乎是体外分枝杆菌感染的PMs产生的唯一主要细胞因子，因此可能单独或与其他细胞因子一起作为分枝杆菌感染的有效生物标志物。
