Title: Cell-Mediated Immune Responses Induced by Hsp65 and hIL-2 Fusion Protein against Mycobacterium Tuberculosis Infection and Its Protective Efficacy in Mice
Abstract: Objective To study the immune responses and protective efficacy induced by heat shock protein 65(Hsp65) and human interleukin 2(hIL-2) fusion protein in mice against tuberculosis infection.Methods Hsp65 and IL-2 fusion protein was expressed in E.coli and purified by Ni-NTA affinity chromatography.The fusion protein was administered to mice in an adjuvant combination of dimethyl dioctadecylammonium bromide(DDA) and monophosphoryl lipid A(MPL).The immunization repeated three times every two weeks.2 wks after the final immunization,5 mice were used for analysis of lymphocyte proliferation index,IL-2,IFN-γ assay and cytotoxic T lymphocyte(CTL) activity in each group.The other 5 were used for a MTB virulent strain attack experiment.Results The fusion protein Hsp65-hIL-2 was purified through Ni-NTA system.The Western blot assay showed that the recombinant protein could respond with the IL-2 mAb and Hsp65 mAb,respectively.The spleen lymphocytes of the fusion protein-immunized mice showed apparent proliferation in response to Hsp65 protein.The fusion protein elicited strong levels of γ-IFN and IL-2 in the lymphocytes culture supernatants,significantly higher than that of the BCG immunized group and single Hsp65 group(P0.05).The spleen cells from mice immunized with fusion protein showed killing activity to the corresponding target cells.A dramatic reduction in the numbers of MTB colony forming units in the spleen was observed in the fusion protein group(4.36±0.48),which provided equivalent protective effect to that afforded by BCG(4.30±0.53).Conclusions Hsp65-IL-2 fusion protein is an effective subunit vaccine against tuberculosis.
Publication Year: 2008
Publication Date: 2008-01-01
Language: en
Type: article
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