Shams Homayoun, Wizel Benjamin, Lakey David L, Samten Buka, Vankayalapati Ramakrishna, Valdivia Raphael H, Kitchens Richard L, Griffith David E, Barnes Peter F
Center for Pulmonary and Infectious Disease Control, University of Texas Health Center, 11937 U.S. Highway 271, Tyler, TX 75708-3154, USA.
FEMS Immunol Med Microbiol. 2003 May 15;36(1-2):63-9. doi: 10.1016/S0928-8244(03)00039-7.
Prior reports have suggested that CD14 mediates uptake of Mycobacterium tuberculosis into porcine alveolar macrophages and human fetal microglia, but the contribution of CD14 to cell entry in human macrophages has not been studied. To address this question, we used flow cytometry to quantify uptake by human monocytes and alveolar macrophages of M. tuberculosis expressing green fluorescent protein. Neutralizing anti-CD14 antibodies did not affect bacillary uptake and the efficiency of bacillary entry was similar in THP-1 cells expressing low and high levels of CD14. However, most internalized bacteria were found in CD14+ but not in CD14- monocytes because M. tuberculosis infection upregulated CD14 expression. We conclude that: (1) CD14 does not mediate cellular entry by M. tuberculosis; (2) M. tuberculosis infection upregulates CD14 expression on mononuclear phagocytes, and this may facilitate the pathogen's capacity to modulate the immune response.
先前的报告表明，CD14介导结核分枝杆菌进入猪肺泡巨噬细胞和人胎儿小胶质细胞，但尚未研究CD14在人巨噬细胞进入细胞过程中的作用。为了解决这个问题，我们使用流式细胞术来量化表达绿色荧光蛋白的结核分枝杆菌被人单核细胞和肺泡巨噬细胞摄取的情况。中和抗CD14抗体不影响细菌摄取，并且在表达低水平和高水平CD14的THP-1细胞中细菌进入细胞的效率相似。然而，大多数内化细菌存在于CD14 +单核细胞中，而不存在于CD14 -单核细胞中，因为结核分枝杆菌感染会上调CD14表达。我们得出以下结论：（1）CD14不介导结核分枝杆菌进入细胞；（2）结核分枝杆菌感染会上调单核吞噬细胞上的CD14表达，这可能有助于病原体调节免疫反应的能力。
