Title: Immune responses and protective efficacy induced in mice by Mycobacterium tuberculosis MPT64-ESAT6 fusion protein
Abstract: AIM: To evaluate humoral and cell-mediated immune responses by MPT64 and ESAT6 fusion proteins and to test protective efficacy against Mycobacterium tuberculosis (MTB) challenge. METHODS: BALB/c mice were immunized 3 times at 2-week interval subcutaneously on the back with fusion protein MPT64-ESAT6. In the spleen lymphocytes of immunized mice stimulation index (SI) was measured by MTT method and the level of secreted IFN-γ was detected by ELISA. Some of vaccinated BALB/c mice by fusion proteins were intravenously infected with 1×105 CFU MTB strain H37Rv. Four weeks later,bacterial load in spleens was determined. RESULTS: The titer of sera specific antibody in BALB/c mice immunized with fusion expression protein MPT64-ESAT6 was 1∶1500. The SI of lymphocytes in fusion protein immunized group was 2.23, significantly higher than that of saline immunized group (0.88). The IFN-γ level in culture supernatant of spleen lymphocytes from the mice immunized with fusion proteins were (4.28±0.27) μg/L, significantly higher than that of saline immunized group [(0.48±0.17) μg/L, P0.05], but lower than that of Bacillus Calmette Guerin (BCG) immunized group [(5.18±0.31) μg/L]. Compared with saline immunized mice(bacterial load was 6.45±0.17), dramatic reductions were observed for MTB replication in the spleen from BALB/c mice immunized with fusion proteins (bacteria load was 5.04±0.11) following a subsequent challenge, but the protective efficacy in mice immunized with MPT64-ESAT6 was not as good as that of BCG immunized group (bac- terial load was 4.38±0.22). CONCLUSION: MPT64 and ESAT6 fusion proteins could be used as a novel component of the new TB vaccine.
Publication Year: 2006
Publication Date: 2006-01-01
Language: en
Type: article
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Cited By Count: 1
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