结核多表位DNA疫苗免疫效果及其对小鼠耐药结核病的疗效观察

摘要

Objective To make a comparative study of the immunogenicity of multi-epitope DNA vaccine and BCG of Mycobacterium tuberculosis and therapeutic effects of the vaccines combined with chemotherapy in a mouse model infected with multi-drug resistant (MDR)Mycobacterium tuberculosis.Methods The BALB/c mice were randomly divided into Group A,Group B and Group C,which received subcutaneous immunization with PBS,BCG and multi-epitope DNA vaccine,respectively,once at weeks 1 ,3 and 5 .Specific IgG antibody,IL2 and IFN-γin mice serum were determined with ELISA after the final vaccination.At the same time,the splenic lymphocytes of mice were separated and the lymphocytes proliferation was determined by MTT method.To study the therapeutic effects of multi-epitope DNA vaccine,the mice were infected by intravenous injection in the tail vein with Mycobacterium tuberculosis clinical isolates that were resistant to isoniazid (INH)and rifampin (RFP).Four weeks later,the model mice were divided into Groups D,E and F.The mice in Group D and control group received saline injection. The mice in Group E were treated with RFP and INH.The mice in Group F were treated with multi-epitope DNA vaccine combined with INH and RFP for 10 weeks.The lungs,livers and spleens of mice were removed and weighed;the colony number of Mycobacterium tuberculosis in the lungs and spleens was counted.Results The antibody IgG,IL2 and IFN-γwere obviously higher in multi-epitope DNA vaccine group than in BCG group (P<0.05).Multi-epitope DNA vaccine combined with chemotherapy could obviously reduce the colony number of Mycobacterium tuberculosis in the lungs and spleens as well as indexes of the lungs,livers and spleens (P<0.05). Conclusion Mycobacterium tuberculosis Hsp70,Ag85A,and ESAT-6 multi-epitope DNA vaccine could induce strong specific immune response in mice that produced a high level of specific IgG antibody,IL2 and IFN-γ,specific lymphocyte proliferation,and significantly improve the efficacy of anti-tuberculosis drug resistant tuberculosis in mice.%目的：研究比较结核分枝杆菌 Hsp70、Ag85A、ESAT-6多表位 DNA 疫苗和卡介苗(BCG)的免疫效果,观察该疫苗联合抗结核药物治疗耐药结核病小鼠的疗效。方法随机将BALB/c 小鼠分成 A、B、C组,分别用 PBS、BCG和多表位DNA疫苗经皮下免疫,1、3、5周各免疫1次。免疫后眼球采血,分离血清,用酶联免疫吸附试验(ELISA)间接法测定特异性 IgG抗体,用 ELISA双抗体夹心法测定 IL2和 IFN-γ；同时分离小鼠脾细胞,用 MTT法测定淋巴细胞增殖指数。为观察多表位疫苗的疗效,小鼠尾静脉注射结核分枝杆菌双耐菌株(耐利福平和耐异烟肼),4周后将感染模型小鼠随机分成D、E、F3组,其中D组为阴性对照,注射生理盐水；E 组用利福平、异烟肼治疗；F 组为联合用药组,用结核分枝杆菌 Hsp70、Ag85A、ESAT-6多表位DNA 疫苗和利福平、异烟肼联合治疗,疗程均为10周。治疗结束后称取小鼠体重,取其肺、肝、脾,称取质量,并作肺和脾脏菌落计数。结果多表位 DNA 疫苗组小鼠血清特异性IgG抗体、IL2、IFN-γ和淋巴细胞增殖指数均明显高于PBS组和BCG组(P<0.05)；多表位 DNA疫苗联合抗结核化疗药能明显降低耐药结核病小鼠肺、脾菌落计数和肺、肝和脾脏指数(P<0.05)。结论结核分枝杆菌 Hsp70、Ag85 A、ESAT-6多表位DNA疫苗能在小鼠体内诱导较强的特异性免疫反应,产生高水平的特异性 IgG 抗体、诱导IL2和 IFN-γ分泌和特异性淋巴细胞增殖,并能显著提高抗结核药物对耐药结核病小鼠的疗效。