Background: Tuberculosis is a disease with high morbidity, caused mainly by Mycobaterium tuberculosis (M.tb.). DNA vaccines show a promising future due to their unique advantages over conventional methods. The early-secreted antigen target (ESAT)-6 and culture filtrate protein (CFP)-10 of M.tb. antigens have been identified as vaccine candidates against Mycobacteria and used as subunit vaccines, DNA or protein, in different studies.
Objective: To investigate the potential of pcDNA3.1+ plasmid containing CFP-10 and ESAT-6 genes in induction of local immune responses after intramuscular injection in BALB/c mice.
Methods: pcDNA 3.1+ CFP-10 and pcDNA3.1+ ESAT-6 plasmids were prepared and defined groups of mice were injected intramuscularly with the plasmids both separately and in combination. The RNA was extracted from muscles after one month and cDNA was made using RT-PCR. The expressions of IL-4, IL-10 and IFN-γ genes cytokines were evaluated using comparative real time PCR.
Results: Expression of IL-4 and IL-10 increased in the injection site of the mice groups which received plasmids encoding ESAT-6 and CFP-10 individually or together. More than 10-fold increase in IFN-γ expression was found in samples taken from mice groups inoculated by plasmids encoding ESAT-6 and CFP-10 individually or together.
Conclusion: pcDNA 3.1+ESAT-6 and pcDNA3.1+CFP-10 plasmids can increase the expression of IFN-γ in mice after immunization.