Table 2

Wild-type Y. enterocoliticia Inhibits the TNF-α Production and Triggers Apoptosis in Murine Peritoneal Macrophages

StimulationTNF-α production*Percent apoptotic cells‡
pg/ml
None 5 ± 13.5 ± 2
LPS88 ± 9ND
WA-C66 ± 44.5 ± 2
WA-31411 ± 3   81 ± 8
  • *  The TNF-α activity in the cell culture supernatant (dilution 1:25) was measured 150 min after the onset of stimulation using a cytotoxic assay performed with the TNF-α–sensitive fibroblast cell line L929.  

  •  Apoptosis was assayed 4 h after onset of stimulation by staining the cells with fluorescein-conjugated annexin V and propidium iodide, and counting apoptotic cells in a fluorescence microscope.