Objectives: To investigate the improvement of specific immune responses induced by plasmid coexpressing hepatitis B surface antigen (HBsAg) and granulocyte-macrophage colony stimulating factor (GM-CSF).
Methods: All Balb/c (H-2d) mice were immunized with pGM-CSF/S, pS/GM-CSF, pS or control plasmids. 4 weeks later, anti-HBs titer and the levels of IL-2, IL-4 and IFN-gamma in the supernatant of splenocytes were detected using enzyme- linked immunosorbent assay (ELISA), and HBsAg-specific cytotoxic T lymphocytes (CTL) activity was measured with a 51Cr release assay, using P815/S transfectants as target cells.
Results: The anti-HBs antibody titers in the serum, the levels of IL-2 and IFN-gamma, and the CTL activity in pcDNA3.1-GM-CSF-S immuned mice were higher than those in PcDNA3.1-S immunized mice (F=4.176, P<0.01; F=31.188, P<0.01; F=31.796, P<0.01; F<or=26.891, P<0.01).
Conclusion: It will improve the specific immune responses induced by HBsAg DNA vaccine after it is binded to the gene of GM-CSF.