Gene(s) in epithelial cells can be upregulated or downregulated by different stimuli in a tissue-specific manner. We used genome-wide microarray analysis to profile the expression of genes in HT-29 cells that are upregulated after stimulation with sodium butyrate (NaB) and subsequently downregulated by the addition of ciprofloxacin antibiotic. The specific aim was to evaluate genes that are associated with mucosal immunity. HT-29 cells were stimulated with sodium butyrate (NaB) (n=3), NaB and ciprofloxacin (n=3) or culture media (unstimulated control, n=3) for 24 hours. RNA extracted from these cells were hybridized on Affymetrix microarrays.