Khanna K V, Choi C S, Gekker G, Peterson P K, Molitor T W
Department of Clinical and Population Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul 55108, USA.
J Leukoc Biol. 1996 Aug;60(2):214-20. doi: 10.1002/jlb.60.2.214.
The resurgence in mycobacterial infection worldwide has led to renewed attention to the pathogenesis of Mycobacterium species. The purpose of this study was to characterize the infection of alveolar macrophages (AMs) by nonopsonized Mycobacterium bovis, and to elucidate the mechanism by which a differential infection of subpopulations of AM may occur. A difference in susceptibility to Mycobacterium bovis infection of subpopulations of AMs was observed, such that the least dense cells were the least susceptible (21.4 +/- 10.7%) and the most dense cells were the most readily infected (61.8 +/- 5.6%). The percentage of AMs staining for CD14 receptors showed a similar differential distribution, with fewer of the least dense cells expressing CD14 and a greater percentage of the most dense cells staining for CD14 receptor expression. To investigate the role of CD14 receptors in the infection of AMs, anti-CD14 antibody was added to the cell cultures. Infection of AM by Mycobacterium bovis was blocked by up to 60.2% by anti-CD14 antibody but not by isotype control antibody. The results of this study suggest that Mycobacterium bovis selectively infects AM subpopulations, specifically those with the greatest expression of CD14, a putative receptor mechanism for Mycobacterium bovis infection of porcine AM.
全球分枝杆菌感染的再度流行引发了对分枝杆菌属发病机制的重新关注。本研究的目的是表征未调理的牛分枝杆菌对肺泡巨噬细胞（AMs）的感染，并阐明AMs亚群可能发生差异性感染的机制。观察到AMs亚群对牛分枝杆菌感染的易感性存在差异，即密度最小的细胞最不易感（21.4 +/- 10.7%），而密度最大的细胞最易被感染（61.8 +/- 5.6%）。对CD14受体染色的AMs百分比显示出类似的差异分布，密度最小的细胞中表达CD14的较少，而密度最大的细胞中染色显示CD14受体表达的百分比更高。为了研究CD14受体在AMs感染中的作用，将抗CD14抗体添加到细胞培养物中。抗CD14抗体可将牛分枝杆菌对AMs的感染阻断高达60.2%，而异型对照抗体则无此作用。本研究结果表明，牛分枝杆菌选择性感染AMs亚群，特别是那些CD14表达最高的亚群，CD14是牛分枝杆菌感染猪AMs的一种假定受体机制。
