Interaction of nanobacteria with cultured mammalian cells

作者：Neva Çiftçioğlu, E. Olavi Kajander · 发表于：Pathophysiology · 年份：1998 · DOI：10.1016/s0928-4680(97)10001-3 · 被引用次数：92 · 研究领域：Cancer Research and Treatments、Animal Genetics and Reproduction、Bacteriophages and microbial interactions

Nanobacteria were recently isolated from human blood and commercial fetal bovine serum (FBS) and were located in the α-2 subgroup of proteobacteria based upon their 16S rRNA gene sequence. They can be cultured even in the absence of mammalian cells, and have extraordinary properties, like very slow growth rate and an impermeable cell wall, making their detection difficult by standard microbiological techniques. Since they are present in FBS, and thus in cell cultures, it is essential to clarify their effects on cultured mammalian cells. In this study, we show that four out of six nanobacterial isolates from different sera exerted a cytotoxic effect on 3T6 fibroblasts verified by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] viability assay, lactate dehygrogenase (LDH) release and by direct microscopy. The cytotoxic effect of nanobacteria was attenuated after they had been subcultured several times. The cytotoxic effect was similar with all tested murine and human fibroblastoid cell lines. Differential interference contrast and electron microscopy, and FITC staining with specific monoclonal antibodies indicated selective, possibly receptor-mediated adherence, followed by internalization and cytotoxicity in the 3T6 fibroblasts used as a model in these interaction studies. Thus, nanobacteria have a special way of invading mammalian cells: they trigger cells that are not normally phagocytic to engulf them. These organisms seem to be an important cause for ce...