[Expression of human IL-12 in mammalian cell and study on its biological activities].

Objective: To obtain recombinant human interleukin 12 by genetic engineering, and to explore possibility of its clinical application in treatment of tumor and chronic hepatitis.

Methods: Bicistronic expression vector P35-IRES-P40 was constructed for the simultaneous translation of IL-12 p35 and p40 cDNA subunit through internal ribosomal entry sites (IRES). pCI-dhfr-P35-IRES-P40 vector was constructed for expression in CHO-DHFR- cells.

[Antigencity identification of recombinant hepatitis E virus ORF2 protein expressed in Pichia pastoris].

Background: To determine the antigenicity of recombinant hepatitis E virus ORF2 (rHEV ORF2) protein expressed in Pichia pastoris (P. pastoris).

Methods: By using the rHEV ORF2 protein from E.

[Baculovirus expression of two human recombinant neutralizing IgG monoclonal antibodies to hepatitis A virus].

Objective: To develop human recombinant neutralizing IgG monoclonal antibodies to hepatitis A virus (HAV) by baculovirus expression system.

Methods: The heavy and light chain genes of two human-derived neutralizing Fab antibodies to HAV were cloned into baculovirus expression vector Pac-kappa-Fc and Pac-L-Fc, and further expressed in insect cells as IgG antibodies. The IgG products were purified and well characterized.

[Antigenic analysis of the common recombinant mutant types of HBsAg].

Background: To study the difference between the mutant types and the wild type of HBsAg on the binding efficiency with antibodies in order to find some methods to detect the mutants.

Methods: The recombinant wild type of HBsAg and the mutants including 145 R, 133 T, 126 S, 141 E, 126 S+133 T, 126 S+133 T+145 R and 126 S+133 T+141 E were cloned, respectively. Then the expression vector containing the wild or mutant gene was transfected into COS7 cells, and the recombinant proteins were expressed.