[Experimental study on immune responses induced in mice by gp120 gene vaccine of Chinese HIV-1 strain].

Aim: To construct the gp120 DNA vaccine of Chinese HIV-1 strain and evaluate the immune responses induced with it in BALB/c mice.

Methods: The recombinant expression vector pVAX1-GP120 was constructed by inserting HIV gp120 gene into the eukaryotic expression vector pVAX1 and confirmed with EcoR I/Pst I and DNA sequencing. BALB/c mice were immunized with pVAX1-GP120 and pVAX1 respectively. The levels of serum anti-HIV antibody and IFN-gamma of the immunized mice were detected by ELISA. The proliferation of splenocytes was determined by MTT colorimetry and the specific cytotoxic T lymphocytes (CTLs) response by LDH assay.

Results: Restriction enzymes digestion analysis and DNA sequencing results revealed that the pVAX1-GP120 had been constructed successfully. The titer of anti-HIV antibody and the IFN-gamma level in mice immunized with the pVAX1-GP120 were higher than those in mice immunized with pVAX1 respectively (P<0.01). As compared with mice immunized with pVAX1 alone, the cytotoxic activity of specific CTLs and antigen-specific lymphoproliferative responses in mice immunized with pVAX1-GP120 were significantly enhanced (P<0.01).

Conclusion: Specific cellular and humoral immune responses in mice can be induced with gp120 gene vaccine of Chinese HIV-1 strain, which lays the foundation for further development of therapeutic HIV vaccine against HIV-1 infection.