Woo Seng-Ryong, Sotos Josh, Hart Arlene P, Barletta Raúl G, Czuprynski Charles J
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA.
Vet Immunol Immunopathol. 2006 Mar 15;110(1-2):109-20. doi: 10.1016/j.vetimm.2005.09.010. Epub 2005 Oct 26.
Bovine monocytes exhibited a greater ability to phagocytose Mycobacterium avium subsp. paratuberculosis (i.e. greater percentage of infected cells, and more bacilli per infected cell), than did a bovine macrophage cell line (BoMac). Phagocytosis of M. paratuberculosis by monocytes, but not the cell line, was significantly enhanced by the addition of autologous serum. Following ingestion, the numbers of viable M. paratuberculosis cells in monocytes increased during the first 4 days and then declined between day 4 and day 8 after infection, as determined by a radiometric method. In contrast, BoMac cells were not permissive for bacillary multiplication; the numbers of M. paratuberculosis remained largely unchanged in the cell line during the 8 day incubation period. The numbers of microscopically visible acid-fast bacilli increased with time in monocytes but not in the macrophage cell line. These observations suggest that replication and inactivation of bacilli may both occur in monocytes. The differing abilities of bovine monocytes and the macrophage cell line to ingest and restrain the intracellular growth of M. paratuberculosis provide contrasting model systems for investigating how M. paratuberculosis enters and persists within its preferred niche, the mononuclear phagocyte.
牛单核细胞比牛巨噬细胞系（BoMac）表现出更强的吞噬副结核分枝杆菌亚种鸟分枝杆菌的能力（即被感染细胞的百分比更高，且每个被感染细胞内的杆菌更多）。单核细胞对副结核分枝杆菌的吞噬作用（而非细胞系的吞噬作用）在添加自体血清后显著增强。摄入后，通过放射性测定法确定，单核细胞内副结核分枝杆菌活细胞数量在感染后的前4天增加，然后在第4天至第8天之间下降。相比之下，BoMac细胞不允许杆菌繁殖；在8天的培养期内，细胞系中副结核分枝杆菌的数量基本保持不变。显微镜下可见的抗酸杆菌数量在单核细胞中随时间增加，但在巨噬细胞系中没有增加。这些观察结果表明，杆菌的复制和失活可能都发生在单核细胞中。牛单核细胞和巨噬细胞系在摄取和抑制副结核分枝杆菌细胞内生长方面的不同能力，为研究副结核分枝杆菌如何进入并在其偏好的单核吞噬细胞生态位中持续存在提供了对比模型系统。
