To identify host genes differentially expressed during Salmonella enterica serotype Typhimurium infection, an RNA differential display was made with total RNA extracted from ileal loops that were infected with Salmonella Typhimurium 2.5 h after infection. Down-regulated cDNA was identified in bovine Peyer's patches after infection that was highly homologous to a human plasma membrane calcium-transporting ATPase (PMCA). Differential expression of PMCA, evaluated by Northern analysis, was found to have more than a 4.6-fold decrease in expression of mRNA (size, approximately 5.1 kb). PMCA mRNA was detected by in situ hybridization exclusively within epithelial cells in the Peyer's patches. cDNA (4.4 kb) was amplified by rapid amplification of cDNA ends, cloned, and sequenced and showed a high homology to hPMCA. Bovine PMCA is down-regulated in epithelial cells of Peyer's patches after infection with Salmonella Typhimurium and, subsequently, may influence cellular calcium levels that contribute to the inflammatory processes in the pathogenesis of diarrhea.
