FIG. 6.

Infection with WT EPEC increases MCP-1 and β-defensin-2 gene expression in Caco-2 cells. Cells were grown to confluence in 12-well plates and subsequently infected with WT EPEC, FliC-deficient (ΔfliC) EPEC, or T3SS-deficient (ΔescN) EPEC for 3 h in 2 ml DMEM without antibiotics and serum. After infection, the cells were washed twice, and fresh medium was added with gentamicin treatment. Total RNA was extracted 6 h after initial infection and subjected to semiquantitative RT-PCR to measure gene expression as described in Materials and Methods. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was included as an internal control.