Global transcriptional response of porcine intestinal epithelial cell lines to Salmonella enterica serovar Typhimurium and Choleraesuis: IPI-2I infected with S. typhimurium

The GeneChip Porcine Genome Array was used to identify the transcriptional response upon either Salmonella typhimurium (ST) or Salmonella choleraesuis (SC) infection in two porcine epithelial cell lines (IPEC-J2, from jejunum and IPI-2I, from ileum) during 2 and 4 hours post infection. The objectives in this study were first, to identify the different response between the epithelial cell lines from different gut regions; second, to study how the Salmonella serotypes used could elicit a different host response; and third, to determine the effect of the time-points on the differentially gene expression. Epithelial cells were seeded into 6-well tissue culture plates and grown to confluence in 5% CO2 at 37ºC. Monolayers were infected for 1 h. with Salmonella typhimurium or Salmonella choleraesuis serotypes (MOI 1:10) or incubated with media alone (Control cells). Extracellular bacteria were removed, and cultures were further incubated during 2 and 4 h. in the presence of 50 µg/ml of the non-cell-permeant antibiotic gentamicin to kill remaining extracellular bacteria. The experiment was developed by triplicate in order to ensure a proper robustness in the microarray statistical analysis. An indirect ELISA was used to confirm cell activation by mean of IL8 detection in cell culture medium. After each time-point, cells were lysed and RNA extracted.