Immortalization of swine umbilical vein endothelial cells with human telomerase reverse transcriptase.

Swine endothelial cells are commonly used as an in vitro model for studying features of the blood-brain barrier and some hemorrhagic diseases. However, primary cultures of swine cells have finite lifespans. To establish immortalized swine umbilical vein endothelial cells (SUVECs) using human telomerase reverse transcriptase (hTERT), the plasmid pCI-neo-hTERT was transfected into SUVECs by lipofection. Clones were selected for G418 resistance, and positive clones were amplified. One of the clones was cultured for up to 50 passages. Factor VIII-related antigen and CD34 were detected. The immortalized cells shared the properties of normal cells, such as contact inhibition, serum requirement and anchorage dependence. Karyotype analysis revealed that the immortalized cells were in the diploid range. In addition, both in vivo and in vitro assays of tumorigenicity showed no neoplastic transformation. Furthermore, NO, PGI2, and ET-1 concentrations in the transfected cells were normal. These results suggest that the SUVECs immortalized by hTERT retain their original characteristics.

Cytopathic effect of classical swine fever virus NS3 protein on PK-15 cells.

In order to further research the relationship between classical swine fever virus' (CSFV) NS3 protein and the cytopathic effect (CPE) in cells infected with the CSFV, and to reveal the effect of protein NS3 on the host cells, the NS3 of CSFV Shimen strain amplified by RT-PCR was subcloned into the pEGFP-C1, named pEGFP-C1-NS3. The insert position, the size and the reading frame were correct for restriction enzyme digestion and sequence analysis. The pEGFP-C1-NS3 and pEGFP-C1 were transfected into PK-15 cells by liposome, and positive cell clones were gained by G418. The NS3-EGFP fusion protein expressed in pEGFP-C1-NS3 cells was observed by inverted fluorescence microscopy and identified by Western blot. The CPE appeared in positive pEGFP-C1-NS3 cells 72 h after passaging, apoptosis detection was also performed on positive pEGFP-C1-NS3 cells and pEGFP-C1 cells 72 h after passaging by TUNEL assay. The apoptosis rates in the positive pEGFP-C1-NS3 and pEGFP-C1 cells were 43.4 and 13.1%, respectively (p < 0.05). The results suggest that the CPE in positive pEGFP-C1-NS3 cells was induced by apoptosis and there is a relationship between the expression of NS3 and apoptosis.