Tumor necrosis factor α (TNFα) is a pro-inflammatory cytokine, acting as a regulator of inflammation and immune response. TNFα plays a critical role in the pathogenesis of rheumatoid arthritis (RA). Blocking of TNFα activity may reduce inflammatory tissue damage. In the present study, the chimeric gene of soluble TNFα receptor and the IgG Fc fragment (sTNFR-IgGFc) have been cloned into the mammalian cell expression vector pStar. When the plasmid pStar/sTNFR-IgGFc-GFP was transfected into endothelial cells, a significant expression of the sTNFR-IgGFc fusion protein was detected. Moreover, the expressed product in 100 μL cell culture supernatant could completely antagonize the cytolytic effect of 1 ng TNFα on L929 cells, even at 1/64 dilution. A preparation of the plasmid was delivered into collagen-induced RA mice by tail vein injection. The expression of sTNFR-IgGFc was detected in liver by RT-PCR. Animals in the treatment group showed reduced symptoms of arthritis and were more active. This treatment reduced the synovial incrassation and prevented cartilage destruction in the joints of the mice, RA model. These results showed that tail vein injection is an effective way for gene therapy and sTNFR-IgGFc expression plasmid DNA is potential for the treatment of RA.

Tumor necrosis factor α plays primary role in the pathogenesis of inflammatory diseases. TNFα is essential for antigen-specific IgE production and for the induction of Th2-type cytokines. The lack of TNFα inhibited the development of allergic rhinitis. In this study, the chimeric gene of soluble TNF receptor and IgGFc fragment (sTNFR-IgGFc) was cloned into the EBV-based plasmid pGEG. When the plasmid pGEG·sTNFR-IgGFc was transferred to endothelium cell, a considerable expression of the sTNFR-IgGFc fusion protein was detected. Moreover, the expression product in the supernatant could antagonize the cytolytic activity of TNFα on L929 cells. Then the plasmid was delivered into nasal mucosa of allergic rhinitis mice to determine its effect on this animal model. Results showed that symptoms in treated group were improved. Pathological examination showed the numbers of eosinophil, mast cell and IL-5(+) cells in treated groups were reduced compared with placebo group. These data showed that pGEG·sTNFR-IgGFc expression plasmid is potential for the treatment of allergic rhinitis, and suggest that the antagonist of TNFα may provide a new approach for the treatment of allergic rhinitis.

OBJECTIVE:To explore the role of BM2 protein in the life cycle of influenza B virus.METHODS:The authors screened human kidney MATCHMAKER cDNA library for new binding partners of BM2 of influenza B virus by using the yeast two hybrid system with truncated BM2 (26-109 aa) as the bait.RESULTS:Six positive plasmids encoding N-acetylneuraminate pyruvate lyase, angiopoietin 3, zinc finger protein 251, ribosomal protein S20, protein arginine N-methyltransferase 1 variant 1 (PRMT) and transcription factor-like 1 (TCFL1) were obtained.CONCLUSION:The results suggest that BM2 may play an important role in the life cycle of influenza B virus.

The nonviral gene delivery systems are usually not very effective in transferring gene into target cells, and the intensity and duration of the gene expression is very poor. The EBNA1/oriP maintain EBNA1/oriP-based plasmids as episome, contribute to nuclear transport of the plasmid and transcriptional up-regulation of target gene. The EBNA1/oriP based plasmid enhances the transfection rate as well as magnitude and longevity of gene expression. This article reviews recent preclinical gene therapy studies with the EBV plasmid vectors conducted against various diseases. For gene therapy against malignancies, the EBNA1/ oriP based plasmid encoding the HSV1-TK suicide gene was combined with a cationic polymer to transfer into HCC cell line. The expression level of TK gene was 100- to 1000-fold higher than the conventional plasmid. The sensitivity of HCC to ganciclovir (GCV) elevated several hundred-fold. The EBNA1/oriP based plasmid equipped with tumor specific promoter, such as CEA promoter, enabled targeted killing of CEA-positive tumor cell. Transfection of EBNA1/oriP based plasmid carrying IL-12 and IL-18 gene either locally, or systemically, induced therapeufic antitumor immune responses including augmentation of the cytotoxic T lymphocyte and natural killer activities and growth retardation of tumors. For gene therapy of congenital diseases and chronic diseases, the EBNA1/oriP based plasmid encoding the adenosine deaminase gene was transfered into human hematopoietic progenitor cells. The ADA activity was elevated 1.5-to 2-fold. Intracardiomuscrlar transfer of the EBNA1/oriP based plasmid encoding the beta-AR gene may be useful for the treatment of severe heart failure. Human tumor necrosis factoralpha (hTNFalpha) is one of the most important inflammatory cytokines. It has been implicated in many autoimmune and inflammatory diseases. sTNFR can efficiently neutralize the bioactivities of hTNFalpha. In primary study we cloned the chimeric protein sTNFR II-IgG Fc and expect to use it in the gene therapy of the inflammatory disease relative to TNF. In summary, The EBNA1/oriP based plasmid shows advantage in gene therapy of cancer, congenital and inflammatory diseases. Moreover, the EBNA1/oriP element may greatly contribute to the engineering of a human artificial chromosome, the ultimate device for controllable gene therapy.