[Preparation of vero cell-adapted influenza H5N1 virus strain by genetic reassortment].

Objective: To prepare Vero cell-adapted influenza H5N1 virus strain by Genetic Reassortment and produce influenza H5N1 vaccine using Vero cell as a substrate.

Methods: Embryonated specific pathogen-free (SPF) hen's eggs and Vero cells were co-infected with Vero cell-adapted influenza virus A/Yunnan/1/2005 Va(H3N2) and A/Anhui/1/2005 (H5N1) via reverse genetics. The reassortant was screened with goat antibody against strain A/Yunnan/1/2005 Va(H3N2) and identified for subtype by hemagglutination-inhibition (HI) assays and gene analysis of HA and NA.

Screening of a high growth influenza B virus strain in Vero cells.

Due to the insufficient supply of embryonated chicken eggs, the preparation of large quantities of inactivated influenza vaccines will require an alternative virus culture system after the emergence or reemergence of a pandemic influenza virus. The Vero cell is one of the ideal options since it was used for producing many kinds of human vaccines. However, most of the influenza viruses can not grow well in Vero cells.

[Research on an improved Lowry method to determine content of protein in Sabin IPV].

Objective: To establish a method for the content determination of protein in Sabin IPV.

Methods: Using lowry method combined with being precipitated by trichloroacetic acid to determine the content of protein in Sabin IPV. Changing different conditions to optimize the experiment to establish a improved lowry method.

[Effective inactivatian test of inactivated hepatitis A vaccine using integrated cell culture/strand-specific reverse transcriptase-polymerase chain reaction].

Objective: To establish an quick, sensitive and specific assay for effective inactivatian test of inactivated hepatitis A vaccine.

Methods: effective inactivatian test of inactivated hepatitis A vaccine were carried out using integrated cell culture/strand-specific RT-PCR (ICC/strand-specific RT-PCR) assay compared with traditional ELISA and nest RT-PCR assay.

Results: all the samples were infectious negative detecting by both ICC/ strand-specific RT-PCR and ELISA assay,while some samples appeared false positive detecting by nest RT-PCR.

[Effect of 2-phenoxyethanol on potency of Sabin inactivated poliomyelitis vaccine and its safety].

Objective: To investigate the effect of 2-phenoxyethanol on potency of Sabin inactivated poliomyelitis vaccine (IPV).

Methods: Sabin IPV samples containing 5 mg or 7 mg 2-phenoxyethanol each dosage respectively were placed separately at 4 degrees C, 37 degrees C for 2 days and 7 days. D-antigen contents were tested with ELISA method.

[Construction of bicistronic vector and its application to combined DNA vaccine].

Background: To study preparation of polyvalent DNA vaccine and the control of multiple gene expression.

Methods: A bicistronic vector pcDNA3.0BA was constructed from pcDNA3.

Expression and self-assembly of HCV structural proteins into virus-like particles and their immunogenicity.

Background: The synthesis of virus-like particles (VLPs) provides an important tool to determine the structural requirements for viral particle assembly and virus-host interactions. Our purpose was to express simultaneously all three structural proteins of hepatitis C virus (HCV) in insect cells to investigate the proteins assembly into VLPs and the immunogenicity of these particles.

Methods: HCV gene sequences encoding the structural proteins C, E1, and E2 were amplified with PCR, and recombinant baculoviruses were constructed using recombinant DNA techniques.

A novel process for production of hepatitis A virus in Vero cells grown on microcarriers in bioreactor.

Aim: To develop a novel process for production of HAV in Vero cells grown on microcarriers in a bioreactor.

Methods: Vero cells infected with HAV strain W were seeded at an initial density of 1 x 10(5) cells/mL into a 7-L bioreactor containing Cytodex-I microcarriers. During the stage of cell proliferation, the following conditions were applied: pH 7.

No requirement of HCV 5'NCR for HCV-like particles assembly in insect cells.

Aim: To express all three HCV structural proteins in the presence or absence of HCV 5'NCR to investigate the requirement of 5'NCR for the assembly of HCV-like particles in insect cells.

Methods: HCV structural protein encoding sequences CE1E2 and 5'NCR-CE1E2 were amplified with PCR. Recombinant baculovirus were constructed with recombinant DNA techniques.