Novel constructs of tuberculosis gene vaccine and its immune effect on mice

A novel tuberculosis (TB) gene vaccine containing mouse granulocyte macrophage-colony stimulating factor (mGM-CSF) and a TB antigen (Ag85A) was developed in this study. The genes encoding Ag85A and mGM-CSF were amplified by PCR respectively from the Ag85A-containing pBSby5 and pC-mGM-CSF. The genes were then cloned into two different polylinker sites of plasmid pIRES, forming a novel TB gene vaccine construct pI85AGM. Following transfection of pI85AGM plasmid into 7721 cell line by Lipofectamine(TM), the expression of Ag85A and GM-CSF proteins was identified by Western blotting or RT-PCR. Then Balb/c mice were inoculated with the recombinant pI85AGM, pI85A, pIGM or plasmid alone, respectively. The activities of CTL, NK cells and the Ag85A-stimulated proliferation of spleen cells were measured by MTT method. The serum antibody against Ag85A was detected by ELISA. The results showed that the Ag85A and GM-CSF proteins could be expressed in 7721 cell line and the activity of CTLs and the proliferation of spleen cells were significantly increased in the pI85AGM-immunized mice, indicating that the pI85AGM-immunized mice could generate specific immune responses to Ag85A. This study might provide possibility for developing novel anti-TB gene vaccine.