The recombinant fusion protein CFP10-ESAT6-dIFN has protective effect against tuberculosis in guinea pigs.

Development of effective vaccine candidates against tuberculosis is currently the most important challenge in the prevention of this disease since the BCG vaccine fails to guarantee a lifelong protection, while any other approved vaccine with better efficiency is still absent. The protective effect of the recombinant fusion protein ESAT6-CFP10-dIFN produced in a prokaryotic expression system (Escherichia coli) has been assessed in a guinea pig model of acute tuberculosis. The tested antigen comprises the Mycobacterium tuberculosis (Mtb) proteins ESAT6 and CFP10 as well as modified human γ-interferon (dIFN) for boosting the immune response. Double intradermal immunization of animals with the tested fusion protein (2 × 0.5 μg) induces a protective effect against subsequent Mtb infection. The immunized animals do not develop the symptoms of acute tuberculosis and their body weight gain was five times more as compared with the non-immunized-infected animals. The animal group immunized with this dose of antigen displays the minimum morphological changes in the internal organs and insignificant inflammatory lesions in the liver tissue, which complies with a decrease in the bacterial load in the spleen and average Mtb counts in macrophages.