Moreover, the lifespan of human cells in vitro is known to be dependent on Remdesivir GS-5734 telomere length and telomerase activity. Telomere shortening in humans is a prognostic marker of disease risk, progression and premature mortality. However, telomere shortening can be counteracted by activity of the cellular enzyme telomerase. Telomerase adds telomeric repeat sequences to the ends of chromosomal DNA, thus preserving telomere length, cellular function, and long-term immune function. The introduction of the hTERT gene is a widely used strategy to extend the lifespan of many cell types and successful immortalization has been reported in human retinal pigment epithelial cells, porcine umbilical vein endothelial cells and cattle type II alveolar epithelial cells. In the present study, primary porcine small intestinal epithelial cells were transfected with the pCI-hTERT-neo plasmid and stable transfectants were selected with G418. The newly established epithelial cell line was detected to have a significantly higher expression of hTERT and higher telomerase activity compared to primary cells, suggesting that the lifespan of pSIECs was successfully extended. Various synthetic culture media, supplemented with 5–20% FBS, have been used in studies of the mammalian intestinal epithelium, And supplementation with ITS or EGF is beneficial for epithelial cell proliferation. In the present study, the addition of 5% FBS was found to be optimal for the growth of ZYM-SIEC02 cells. ITS supplementation promoted cell proliferation, while the combination of ITS and FBS further enhanced proliferation. In contrast, EGF had minimal effects on the proliferation of ZYM-SIEC02 cells. Overall, our data suggests that ITS can partially substitute for the mitogenic effects of FBS and is capable of sustaining proliferation of ZYM-SIEC02 cells, which is beneficial for future studies on viral infection. The newly established ZYM-SIEC02 cell line was not transformed and was not tumorigenic in nude mice, indicating that this cell line can be used in addition to pSIECs. Furthermore, we found that this cell line closely mimics the porcine intestinal environment in vivo, contributing to the establishment of a porcine-derived infection model. The functionality of the intestinal epithelium is critically important to neonatal swine as this period of time represents a window of significant vulnerability to pathogens including Salmonella enteria serovar typhimurium. Moreover, we detected the invasion efficiency of S. Typhimurium in the ZYM-SIEC02 cells and found S. Typhimurium could invade host cells effectively and we used MOI of 100:1 to ensure enough number of intracellular bacteria. Cytokines impact on the functional state of immune cell populations by eliciting altered patterns of gene expression.