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Xue-Fan Bai

Publications and source records attributed to Xue-Fan Bai.

8 recordsLinked to original sources
PubMed2005

Stable inhibition of hepatitis B virus expression and replication by expressed siRNA.

RNA interference might be an efficient antiviral therapy for some obstinate illness. Here, we studied the effects of hepatitis B virus (HBV)-specific 21-nt small interfering RNAs (siRNA) on HBV gene expression and replication in 2.2.15 cells. Seven vectors expressing specific hairpin siRNA driven by the RNA polymerase II-promoter were constructed and transfected into 2.2.15 cells. In the cell strain that can stably express functional siRNA, the HBV surface antigen (HBsAg) and the HBV e antigen (HBeAg) secretion into culture media was inhibited by 86% and 91%, respectively, as shown by an enzyme-linked immunosorbent assay. Immunofluorescence and Western blot indicated similar results. HBV DNA was markedly restrained by 3.28-fold, as assessed by the fluorescent quantitation PCR. Moreover, the HBV mRNA was significantly reduced by 80% based on semiquantitative RT-PCR. In conclusion, the specific siRNA can knock down the HBV gene expression and replication in vitro, and the silence effects have no relationship with interferon response.

Cell Line, Tumor↗
PubMed2005

[Exosome: Trojan horse in immunotherapy].

Exosomes are small membrane-bound vesicles that are secreted by a multitude of eukaryocytes as a consequence of fusion of multivesicular bodies with the plasma membrane. Exosomes can play critical roles in different physiological processes depending on their origins. Exosomes secreted from professional antigen-presenting cells are enriched in MHC class I and II complexes, costimulatory molecules, hsp 70 and hsp 90 chaperones, therefore exosomes, like Trojan horse, are of importance of immunoregulation in vivo and in vitro. The review will present current trends of research on the fundamental properties, production and purification of exosomes, and will focus on their implementation in cancer and virus immunotherapy as a novel cell-free peptide-based vaccine.

Animals↗
PubMed2004

[The relationship between cellular infection by Hantaan virus and expression of beta3 integrin].

OBJECTIVE: To investigate the relationship between cellular entry of Hantaan virus (HTNV) and expression of beta3 integrin in beta3-integrin-deficient and HTNV-insusceptible China hamster ovary (CHO) cells. METHODS: Eukaryotic expression vector encoding human integrin beta3 and eukaryotic expression vector harboring human integrin alphav or alphaIIb subunit cDNA were transfected into HTNV non-permissive CHO cells individually or collectively. Screening for stable transfectant clones was performed using G418 selective (culture medium. The exogenous gene expression was analyzed qualitatively and quantitatively by immunofluorescence assay (IFA) and flow cytometry (FCM). Various modified CHO cells and untransfected CHO cells were infected using HTNV A9. At various time points after infection, HTNV antigens in infected cells were detected qualitatively and quantitatively by IFA, FCM. RESULTS: Highly-effective surface expression of beta3 integrin was measured in CHO/alphavbeta3 and CHO/alphaIIbbeta3, while weaker surface expression was detected in CHO/beta3 (P < 0.05). Expression of alphav or alphaIIb integrin in the individually transfected group was significantly lower than in the cotransfected group (P < 0.01) and the sites of localization changed. In contrast, effective surface expression was not seen when pcDNA3 was transfected alone. The infection rate of CHO/alphavbeta3 (60.1%) and CHO/alphaIIbbeta3 (55. 9%) cells were significantly higher than that of CHO/beta3 (38.7%) cells, while the infection rate of CHO/beta3 was significantly higher than that of CHO/alphav, CHO/pcDNA3 and CHO cells respectively. There was a close relationship between the positive percentage of HTNV A9-infected cells and expression of beta3 integrin. CONCLUSION: These results indicated that cellular entry of HTNV was related to the expression of beta3 integrin.

Animals↗
PubMed2003

Hepatic stem cells: existence and origin.

Stem cells are not only units of biological organization, responsible for the development and the regeneration of tissue and organ systems, but also are units in evolution by natural selection. It is accepted that there is stem cell potential in the liver. Like most organs in a healthy adult, the liver maintains a perfect balance between cell gain and loss. It has three levels of cells that can respond to loss of hepatocytes: (1) Mature hepatocytes, which proliferate after normal liver tissue renewal, less severe liver damage, etc; they are numerous, unipotent, "committed" and respond rapidly to liver injury. (2) Oval cells, which are activated to proliferate when the liver damage is extensive and chronic, or if proliferation of hepatocytes is inhibited; they lie within or immediately adjacent to the canal of Hering (CoH); they are less numerous, bipotent and respond by longer, but still limited proliferation. (3) Exogenous liver stem cells, which may derive from circulating hematopoietic stem cells (HSCs) or bone marrow stem cells; they respond to allyl alcohol injury or hepatocarcinogenesis; they are multipotent, rare, but have a very long proliferation potential. They make a more significant contribution to regeneration, and even completely restore normal function in a murine model of hereditary tyrosinaemia. How these three stem cell populations integrate to achieve a homeostatic balance remains enigmatic. This review focuses on the location, activation, markers of the three candidates of liver stem cell, and the most importantly, therapeutic potential of hepatic stem cells.

Animals↗
PubMed2003

[Inhibition of momordica anti-HIV protein of MAP30 on HBeAg expression by laser scanning confocal microscopy].

AIM: To investigate the effect of momordica anti-HIV protein of M(r ) being 30 000 (MAP30) on HBV expression by laser scanning confocal microscopy. METHODS: HBV DNA-transfected hepatocarcinoma cells 2.2.15 were cultured in the presence of MAP30. Then quantitative analysis of HBeAg expression in the 2.2.15 cells by laser scanning confocal microscopy after indirect immunofluorescence staining was performed. RESULTS: The fluorescence intensity in 2.2.15 cells co-cultured with MAP30 was notably weaker than that in control cells. CONCLUSION: MAP30 can effectively inhibit HBeAg expression in the 2.2.15 cells.

Cells, Cultured↗
PubMed2003

[Construction of human integrin beta3 subunit eukaryotic expression vector and efficient surface expression of integrin alphaIIbbeta3].

AIM: To establish efficient surface expression of Homo sapiens integrin alphaIIbbeta3 in beta3-integrin-deficient and HV-insusceptible CHO cells, so as to lay the foundation for the further study of cellular entry of hantavirus mediated by beta3 integrins. METHODS: Eukaryotic expression vector pcDNA3.1-beta3 harboring ORF region of human integrin beta3 subunit cDNA was constructed, then pcDNA3.1-beta3 and eukaryotic expression vector pBJ1-alphaIIb containing human integrin alphaIIb subunit cDNA were transfected into CHO cells alone or together. The expression of exogenous genes were analyzed by indirect immunofluorescence assay (IFA). RESULTS: The eukaryotic expression vector pcDNA3.1-beta3 was constructed successfully. IFA examination showed that surface expression of integrin alphaIIb beta3 was highly effective in cotransfection group, while surface expression was weak on CHO cells transfected with pcDNA3.1-beta3 alone,and no effective surface expression was found in pBJ1-alphaIIb-transfected group. CONCLUSION: Efficient surface expression of integrin alphaIIb beta3 requires expression of both subunits.

Animals↗