Evaluation of protective effectiveness of two tuberculosis DNA vaccines in relation to pathological changes in lung, liver and spleen / 解放军医学杂志

ABSTRACT

Objective To evaluate the protective effectiveness of MPT64 and ESAT6 DNA vaccines against M. tuberculosis. Methods BALB/c mice were randomly divided into 14 groups and subjected to following treatments respectively, i.e. immunized with. ESAT6 (25?g)+MPT64 (25?g)(A), ESAT6(100?g)+IFN-?(100?g) (B), ESAT6 (75?g)+MPT64 (25?g)(C), ESAT6(100?g)+IL-12(100?g) (D), MPT64(100?g)+IL-12(100?g) (E), ESAT6 (25?g)+MPT64 (75?g)(F), MPT64 (100?g)(G), Pvax1 (H),ESAT6 (100?g)(I), ESAT6 (100?g)+MPT64 (100?g)(J), ESAT6 (50?g)+MPT64 (50?g)(K), MPT64(100?g)+IFN-?(100?g)(L), BCG(M ), and saline(N). Then they were infected with M. tuberculosis H37Rv via intravenous route. The pathological changes in the lung, liver, and spleen were observed after the infection. Results Eight weeks after the inoculation, there were only alveolar exudation and capillary hyperemia in the lung lesions in the mice of group N. In the mice of group M and J, main pathological changes included tuberculous granulomas consisting of numerous lymphocytes, macrophages, epithelioid cells and Langhans giant cells, and moderate hyperplasia in alveolar walls. The lung lesions of the other groups were similar, and both hyperplasia and exudate were found (A, B, C, D, E, G, H, I, K, L). No necrosis was found in all the above groups. There were hyperemia, dense lymphocytes infiltration in the portal area, and tuberculous granuloma in the liver in all the groups. No difference was found among all the groups. The pathological changes in spleen induced hyperplasia and fusion of splenic lymph nodule. The reactions in group M and J were stronger than that of the other groups. Conclusions MPT64 and ESAT6 DNA vaccines from M.tuberculosis could enhance immunity against M. tuberculosis, either they were used in combination with different dosages or with IL-12 or IFN-?. The vaccine used in group J showed the strongest effect in enhancing immunity, almost reaching that of combined use of BCG, IFN-? and IL-12.