Comparative study on two DNA vaccines of tuberculosis Ag85A antigen / 中华传染病杂志

ABSTRACT

Objective To explore new method for enhancing the efficacy of tuberculosis DNA vaccine. Methods Two recombinant plasmids were constructed, one named as pBK GM/85A encoding mouse granulocyte macrophage colony stimulating factor(GM CSF) fused to Mycobacterium tuberculosis Ag85A antigen, the other named as pBK 85A encoding Mycobacterium tuberculosis Ag85A antigen alone. Subsequently, the two plasmids were transferred into cultured COS7 cells by using cationic liposomes. The expression products were identified by Western blotting. Then, in a murine model, we compared the immunogenicity and protective immunity of the two recombinant plasmids following genetic immunization. Results All pBK GM/85A injected mice elicited higher antibody titres than that for pBK 85A injected mice. Lymphocytes obtained from the spleen of pBK GM/85A immunized mice exhibited higher lymphocyte proliferative response、IFN ? production and CTL activity than that for pBK 85A immunized mice. The protective efficacy was also higher for pBK GM/85A immunized mice than that for pBK 85A immunized mice. However, The protective efficacy for pBK GM/85A immunized mice was lower than that for BCG immunized mice. Conclusion These results showed that DNA vaccines with GM CSF/antigen fusion constructs could greatly improve the immunogenicity of DNA vaccine against Mycobacterium tuberculosis.