应用结核病DNA疫苗治疗小鼠耐多药结核病的研究

目的 研究结核分枝杆菌Ag85A质粒DNA疫苗单独或联合药物治疗小鼠耐多药结核病的效果,为建立耐多药结核病的免疫治疗新策略和新方案奠定基础.方法 用结核分枝杆菌高耐利福平、低耐异烟肼临床分离株HB361尾静脉注射17～19 g的6～8周龄雌性BALB/C小鼠后,将小鼠随机分为6组,每组10只.感染后第2天开始,分别用pVAX1载体(A组)、利福平(B组)、吡嗪酰胺(C组)、Ag85A质粒DNA疫苗(D组)、Ag85A质粒DNA疫苗联合利福平(E组)、Ag85A质粒DNA疫苗联合吡嗪酰胺(F组)治疗60 d.治疗结束后4周,分别取肺、肝和脾观察病理改变,称取重量,做菌落计数.结果 小鼠感染4周后,肺内菌量达到1.5×107 CFU,脾内菌量达到1.1×106 CFU.A、B组小鼠死亡率均为10%,其余各组小鼠均存活.治疗结束后4周,肺组织病理显示,各治疗组肺组织病变均有不同程度减轻,病变局限,可见正常的肺泡结构,肺泡轮廓相对清晰.与A组比较,C、D、E、F组肺组织菌落数分别减少了1.18、1.35、1.38、1.08 logs,脾脏菌落数分别减少了0.91、1.00、1.26、1.03 logs(P＜0.01).结论 结核分枝杆菌Ag85A质粒DNA疫苗单独或联合药物治疗小鼠耐多药结核病均有显著疗效.Ag85A质粒DNA疫苗与抗结核药物联合治疗是治疗耐多药结核病的最有前途的免疫策略.

Application of DNA vaccine in treatment of mice with multi-drug resistant tuberculosis

Objective To establish foundation for new strategy and program on immune therapy of multi-drug resistant tuberculosis (MDR-TB) by studying the therapeutic effects of Mycobacterium tuberculosis Ag85A plasmid DNA vaccine alone or combined with drugs on MDR-TB mice. Methods Sixty 6-8 weeks old female BALB/C mice were injected via tail vein with clinical isolate Mycobacterium tuberculosis HB361 which was highly resistant to rifampin (RFP) and lowly resistant to isoniazid. The mice were randomly divided into six groups, ten mice in each group. From the second day after infection,the mice respectively received pVAX1 vector (group A), RFP (group B), pyrazinamide (PZA) (group C),Ag85A plasmid DNA vaccine (group D), Ag85A plasmid DNA vaccine combined with RFP (group E),Ag85A plasmid DNA vaccine combined with PZA (group F) for sixty days. Four weeks after the end of treatment,the lung, liver and spleen of the mice were taken and their pathological changes, weight and colony count were examined. Results Four weeks after infection, the numbers of bacteria in lung and spleen of the mice reached up to 1.5×107 CFU and 1.1 × 106 CFU,respectively. The death rates of mice in group A and group B were both 10% ,and the mice in other groups were alive. Four weeks after the end of treatment,lung pathology in the treated groups showed that the lung lesions were slight and limited,normal alveolar structure were seen, and the profile of the alveoli was relatively clear. Compared with group A, group C, D, E, F reduced by 1.18,1.35,1.38,1.08 logs on the colony count of lung, and reduced by 0.91,1.00,1.26 and 1.03 logs on the colony count of spleen (P＜0.01), respectively. Conclusions Mycobacterium tuberculosis Ag85A plasmid DNA vaccine alone or combined with drugs has significant therapeutic effects on MDR-TB mice. Ag85A plasmid DNA vaccine combined with anti-tuberculosis drugs is the most promising immunization strategy for treatment of MDR-TB.