OBJECTIVETo construct SD rat immortalized dental follicle cells (rDFC) induced by simian virus 40 large tumor antigen (SV40Tag) gene to provide a reliable cell source for periodontal tissue engineering research.

METHODSThe rDFC was isolated by tissue mass method combined with enzyme digestion method and evaluated by immunohistochemistry. Cell293 were transfected with plasmid pSSR69/pAmpho containing SV40Tag gene by mediating liposome. Normal rDFC were infected with virus-contained supernate and the successfully transfected cell lines were screened with hygromycin, and positive clones were cultured. While non-transfected cells served as negative controls, the cell morphology was observed, the proliferation characteristics was evaluated by calculating cell population. The expression of SV40Tag gene and telomerase in cells was detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting respectively. The biological property of immortalized rDFC was assessed with calculating formation rate of flat cloning, soft agar colony formation test and tumor-forming test.

RESULTSMorphology of immortalized rDFC was not different from that of normal rDFC. The RT-PCR results of SV40Tag revealed amplification band at 357 bp, while no band was seen in the normal cells. The expression of telomerase in immortalized rDFC was higher than that in normal rDFC. The two groups had no significant difference in growth curves, but the immortalized rDFC exhibited stronger proliferative activity. No significant differences of formation rate in flat cloning were observed between the immortalized rDFC [34% (33/96)] and normal rDFC at passage four [22% (21/96)] (χ(2) = 3.71, P > 0.05). No cell cloning was seen in soft agar and the tumor formation was not observed in nude mice.

CONCLUSIONSThe rDFC induced by SV40Tag gene could be cultured and passaged in vitro, which retained the stable proliferation and differentiation characteristics and could be used for periodontal tissue engineering research.

Animals ; Antigens, Viral, Tumor ; genetics ; metabolism ; Cell Differentiation ; Cell Proliferation ; Cell Transformation, Viral ; Cells, Cultured ; Dental Sac ; cytology ; immunology ; metabolism ; HEK293 Cells ; Humans ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Plasmids ; Rats ; Rats, Sprague-Dawley ; Simian virus 40 ; genetics ; immunology ; Telomerase ; metabolism ; Transfection

Animals ; Cell Culture Techniques ; methods ; Cell Line ; Cell Proliferation ; Hepatocytes ; cytology ; metabolism ; Humans ; Liver ; cytology ; Liver Diseases ; therapy ; Liver, Artificial ; Mice ; Recombination, Genetic ; Simian virus 40 ; genetics ; Telomerase ; genetics ; metabolism ; Transfection ; Tumor Suppressor Protein p53 ; biosynthesis

Immortalized human precartilaginous stem cells (IPSCs) were established to provide stable cell resource for the study of the molecular mechanism of gene targeting on the differentiation of PSCs. Plasmid pCMVSV40T/PUR containing simian virus 40 large T antigen gene (SV40Tag) was transfected into human PSCs by using lipofectin transfection. Colonies were isolated by puromycin selection and expanded by multiple passages. Immunohistochemistry, RT-PCR and Southern blotting were used to identify the transfected cells and to detect the expression and integration of SV40Tag in expanded cell lines. The positive colonies were isolated and subcultured, designated immortalized precartilaginous stem cells (IPSCs), which were confirmed as fibroblast growth factor receptor-3 (FGFR-3) positive cells by immunohistochemistry and RT-PCR. SV40Tag cDNA was found in cultured IPSCs of passage 8 by Southern blotting, and the expressions of SV40Tag mRNA and protein were confirmed by RT-PCR. These findings suggested that IPSCs strain with SV40Tag was constructed successfully.
Cartilage/*cytology ; Cell Proliferation ; Cell Transformation, Viral ; Cells, Cultured ; Fetus ; Simian virus 40/*genetics ; Stem Cells/*cytology ; Transfection

BACKGROUNDAlthough DNA vaccine is considered as the next generation of vaccine, most DNA vaccine candidates are still suffering from the relatively weak immunogenicity despite the increased dosage of plasmid DNA administered. In order to enhance the immune responses elicited by a codon-optimized HIV gag DNA vaccine, a modified plasmid vector pDRVI1.0 and a booster immunization with replicating Tiantan vaccinia (RTV) strain expressing the same gene were employed.

METHODSVector pDRVI1.0 was constructed through inserting the 72-bp element from the SV40 enhancer, which was reported promoting nuclear transport of plasmid DNA, to the upstream of cytomegalovirus enhancer/promoter region of the plasmid vector pVR1012. Gene expression levels from expression plasmids based on pDRVI1.0 and pVR1012 were tested. Humoral and cellular immune responses induced by DNA vaccine alone or DNA prime-RTV boost regimen were determined in mice.

RESULTSIt was shown that the 72-bp element significantly enhanced the gene expression level in non-dividing cells. gag-specific humoral and cellular immune responses induced by DNA vaccination were both significantly improved, while the Th1/Th2 balance was not obviously affected by the 72-bp element. RTV boosting further significantly enhanced DNA vaccine-primed antibody and T cell responses in a Th1-biased manner.

CONCLUSIONSThe 72-bp SV40 enhancer element should be included in the DNA vaccine vector and RTV strain is a very efficient live vector for boosting immunization.

AIDS Vaccines ; immunology ; Amino Acid Sequence ; Animals ; Blotting, Western ; CD8-Positive T-Lymphocytes ; immunology ; Enhancer Elements, Genetic ; Female ; Gene Products, gag ; immunology ; HIV Antibodies ; blood ; Immunoglobulin G ; blood ; Mice ; Mice, Inbred BALB C ; Molecular Sequence Data ; Plasmids ; Simian virus 40 ; genetics ; Vaccination ; Vaccines, DNA ; immunology ; Vaccinia ; immunology

Base Sequence ; Cell Line, Tumor ; Enhancer Elements, Genetic ; genetics ; HT29 Cells ; Humans ; Luciferases ; genetics ; metabolism ; Molecular Sequence Data ; Plasmids ; genetics ; Polymerase Chain Reaction ; Promoter Regions, Genetic ; genetics ; Recombinant Fusion Proteins ; genetics ; metabolism ; Simian virus 40 ; genetics ; Telomerase ; genetics ; Transcription, Genetic ; Transfection

OBJECTIVETo investigate whether simian virus 40 (SV40) was related to patients of malignant mesothelioma in China.

METHODSParaffin-embeded samples of 17 patients with malignant mesothelioma were collected. After isolation of DNA from paraffin blocks, polymerase chain reaction (PCR) analyses were performed using three different sets of primer for detection of SV40 large T antigen gene. These samples were also immunohistochemically evaluated for expression of SV40 TAg protein with two different anti-SV40 Tag (Pab101 and Ab-2).

RESULTSOnly one of the three primer pairs successfully amplified SV40 genome in three malignant mesothelioma samples. No immunopositive staining for SV40 TAg was found in any of the samples.

CONCLUSIONSThe study shows that malignant mesothelioma in China may be independent of SV40 infection.

Adult ; Aged ; Antigens, Viral, Tumor ; genetics ; metabolism ; China ; Female ; Host-Pathogen Interactions ; Humans ; Immunohistochemistry ; Male ; Mesothelioma ; pathology ; virology ; Middle Aged ; Polymerase Chain Reaction ; Polyomavirus Infections ; pathology ; virology ; Simian virus 40 ; genetics ; immunology ; physiology ; Tumor Virus Infections ; pathology ; virology ; Young Adult

Cell Line ; Clone Cells ; cytology ; metabolism ; Cloning, Molecular ; Genetic Vectors ; genetics ; Hepatocytes ; cytology ; metabolism ; Humans ; Simian virus 40 ; genetics ; Transfection

OBJECTIVETo immortalize human umbilical vein endothelial cells (HUVECs) by ectopic expression of the telomerase reverse transcriptase enzyme (hTERT), and by Simian Virus 40 Large T (SV40LT) antigen without malignant transformation.

METHODSTwo different retroviruses that contained hTERT/SV40LT cDNA fragment and drug resistance gene were constructed, and were used to transfect normal primary HUVECs. The transfected cells were screened with 500 microg/ml G418 and 4 microg/ml puromycin. Drug resistance cell clones were selected 3 days after transfection and cultured for further studies. An under inverted microscope and a scanning electron microscope were used to observe the morphology and growth of the cells. The expression of VIII factor and transfected DNA fragments were detected for identification of the endothelial origin and successful transfection. And the expression of E-selectin and endothelial lipase with or without the stimulus of TNF-alpha were also assayed to analyze the biological activity of the transfected cells.

RESULTSThe cells were homogenous, closely apposed, large, flat, and polygonal, displayed a characteristic ovoid nucleus with one or two nucleoli and formed monolayer with polygonal shape without overlapping. Immunocytochemical staining showed the existence of VIII factor. SV40LT/hTERT antigen expressed by the transfected cells was detected, while the contrasts had non-expression. Telomerase activity of the cell was detected in the transfected cells, which was 0.36 at 12 th passage and 0.38 at 50 th passage. However, the activity in the normal HUVECs was 1.12 at the first passage and 0.06 at the third passage assayed by PCR-ELISA. Both E-selectin and endothelial lipase were all specific in endothelial cells. The expressions of these two were also detected. And the expression of E-selectin can be up-regulated with the stimulus of TNF-alpha, while the expression of endothelial lipase was not unregulated significantly.

CONCLUSIONEctopic expression of hTERT and SV40LT can effectively immortalize HUVECs without tumorigenesis.

Antigens, Polyomavirus Transforming ; genetics ; Cell Line, Transformed ; Endothelial Cells ; cytology ; metabolism ; Humans ; Simian virus 40 ; immunology ; Telomerase ; genetics ; Transfection ; Umbilical Veins ; cytology

OBJECTIVETo establish human colorectal crypt cell line.

METHODSColorectal crypt cells were separated from human fetal gut by dispase I digestion, AKP-negative cells from fetal colorectal crypt were collected and cultured on Matrigel matrix. Subsequently the primary cultured cells were transfected with recombinant retrovirus containing human telomerase reverse transcriptase (hTERT) and simian virus 40 large T antigen (SV40 LT) in 48 h. The characterization of immortalized cells was identified after the transfection and cells were screened with antibiotics for 12 approximately 16 weeks and expanded.

RESULTSMucin, cytokeratin-pan, 8, 19 were presented in immortalized cells by immunohistochemical staining; ectopic expressions of both hTERT and SV40 LT were also found in immortalized cells by Western blotting. Agarose electrophoresis showed that the cells expressed Musashi-1 mRNA. No evidence of carcinogenesis was found in nude mouse experiment and soft-agarose cloning test.

CONCLUSIONThe immortalized human colorectal crypt cells were characterized and the established cell line may be an ideal target for carcinogenesis study in vitro.

Cell Line, Transformed ; Colon ; cytology ; DNA-Binding Proteins ; Fetus ; Humans ; RNA, Neoplasm ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Simian virus 40 ; immunology ; Stem Cells ; cytology ; Telomerase ; genetics ; metabolism ; Transcription, Genetic ; Transfection ; methods

Animals ; Cells, Cultured ; Drugs, Chinese Herbal ; pharmacology ; Endothelin-1 ; biosynthesis ; genetics ; Hepatocytes ; metabolism ; Liver ; cytology ; metabolism ; Liver Cirrhosis ; prevention & control ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Simian virus 40 ; genetics ; Transfection