Expression of CTB-human Insulin(BA) Fusion Protein in Gynostemma Pentapyhllum Makino Callus Cells and Its Hypoglycemic Effect in Mice

The plant expression vector of choleratoxin B subunit（CTB）-human insulin（BA） fusion protein pBI121/（CTB-BA） was constructed first and then the Gynostemma Pentapyhllum Makino callus cell line that could express CTB-human insulin fusion protein was constructed and its hypoglycemic effect was evaluated in mice. The plant expression vector pBl 121/（CTB-BA） was digested with both BamI and SacI. Agrobacterium tumerfaciens strain LBA4404 was transformed with previously constructed recombinant plasmid pBI121/（CTB-BA） via the freeze thawing method, then CTB-BA gene was integrated to G Pentapyhllum Makino callus cells by co-culturing the cells with the transformed LBA4404 strain. The transformed G Pentapyhllum Makino callus cells were identified by DNA sequence assey and RT-PCR. The expressed product was identified by western-blot and its amount was tested by ELISA kit and its blood sugar decreasing effect was tested in mice. The sequences of synthetic CTB and human insulin genes（BA） were completely identical to those designed. Restriction map proved that the length of gene fragment in- serted into expression vector pBI121 was consistent with that expected. The sequence of genomic DNA of expressed product was completely identical to that designed. The result of RT-PCR was consistent with that expected. The expressed product showed a specific band with a relative molecular mass of 17000 by Western-blot. The human insulin expression amount was 6.03 μIU/mL according to the ELISA result. The animal test showed that only the G Pentapyhllum Makino callus cell line itself showed activity in decreasing the blood sugar of mice, however, the activity of the transformed G Pentapyhllum Makino callus cells was much higher, The plant expression vector pBI121/（CTB-BA） was constructed and expressed in the G Pentapyhllum Makino callus cells successfully for the first time. The trans- formed G Pentapyhllum Makino callus cells showed high activity in decreasing the blood sugar of mice. This study developed a new way for the development of oral administration insulin.

Immunogenicity and Efficacy of Liposome-encapsulated Influenza Split Vaccine in BALB/c Mice

The cellular immunity of current influenza split vaccine is relatively low. It is necessary to develop a novel vaccine to improve the cellular immunity. The authors of this study prepared liposome-encapsulated influenza split vaccine and tested it in BALB/c mice. The mice were immunized once with 4 μg of haemagglutinin of monovalent A/ New Caledonia/20/99 （H1N1 ） encapsulated with liposomes or the split virus vaccine only through intrastomach injection. In a comparative study, it was observed that the liposome-encapsulated vaccine elicited a higher neutralizing antibedy response, more effectively stimulated spleen cell proliferation, increased cell subsets like CD^4＋ and CD^4＋/ CD8^＋ , and triggered IL-4 and IFN-γ production.

Immune Responses to a Dicistronic Plasmid Expressing HBsAg of Hepatitis B Virus and Interferon-γ

DNA vaccines encoding a viral protein have been shown to induce antiviral immune responses and provide pro-tection against subsequent viral challenge. The present article deals with the efficacy of a DNA vaccine greatly im-proved by the simultaneous expression of HBsAg and interferon-T gene. We constructed a dual expression vector pHIN encoding the HBsAg of Hepatitis B virus and murine IFN-T which are connected with Internal Ribosome Entry Site（IRES）. Mice immunized with this dual expression DNA vaccine exhibited the enhancement of cellular immune response and increased the production of anti-HBV surface antibody, compared with the mice of single gene expres-sion control. Taken together, these results demonstrate that the application of a cytokine gene in a DNA vaccine for-mulation as an adjuvant can improve its immunigenicity.