ABSTRACT
Objective:To investigate the immune efficacy after sequential immunization with Mycobacterium tuberculosis DNA vaccine encoding mature form of Ag85B(pTB30m)and Mycobacterium tuberculosis H37Ra in mice.Methods:Much of highly pure plasmid DNA(pTB30m)extracted by alkaline lysis method was confirmed by restriction endonuclease digestion.Then,its DNA concentration and purity were determined by UV spectrophotometry.At various intervals(4weeks,8weeks)after sequential immunization,ELISA was used to detect the level of the serum antibody against PPD.Also,the spleen lymphocytes of mice were cultured with PPD in vitro.Lymphocyte transformation was detected by MTT assay.Results:Prepared pTB30m was highly pure and came to the needed concentration.Compared with Group Naive control,the specific antibody levels against PPD and the stimulation index(SI)of spleen lymphocytes were all statistically higher in Group DNA-85B/H37Ra(P0.05),as compared with Group DNA-85B/BCG,Group H37Ra and Group BCG,However,compared with Group H37Ra and Group BCG,the SI of mice was significantly larger in Group DNA-85B/H37Ra(P