【摘要】 目的研究含信号肽MTB8.4基因疫苗的免疫原性及对小鼠结核杆菌感染的免疫保护作用。方法雌性C57BL/6N小鼠32只,随机分为4组,即含信号肽的MTB8.4(MS)基因疫苗组、BCG组、pcDNA3.1+组和PBS组。ELISA检测小鼠脾细胞培养上清中细胞因子水平;并按效、靶比例分别为100∶1、50∶1、10∶1进行CTL杀伤检测。用结核杆菌H37Rv强毒株静脉攻击小鼠,计数肺和脾组织中的结核杆菌菌落数,观察小鼠部分肺和脾组织的病变程度;Z-N染色查结核杆菌,观察该疫苗对小鼠结核杆菌感染的免疫保护作用。结果MS基因疫苗能够诱导较强的抗原特异性Th1型细胞免疫应答,细胞因子IFN-γ和IL-2分泌增加,IL-4分泌减少,特异性CTL活性增加;免疫组小鼠肺和脾组织中的结核杆菌菌落数较空载体组显著减少,组织病变明显减轻。结论结核病MS基因疫苗能诱导较强的Th1型细胞免疫应答,对小鼠结核杆菌感染有一定的免疫保护作用,但尚需进一步提高。更多还原

【Abstract】 Objecticve To study the immunogenicity and protective effecacy of MTB8.4 with signal peptide gene vaccine against TB in mice.Methods C57BL/6N!mice were vaccinated with MTB8.4 with signal peptide（MS） gene vaccine three times at 3 weeks intervals.Four weeks after the final vaccination,three mice were sacrificed to assess cytokine response and CTL induction and the other five mice were challenged intravenously in a lateral tail vein with(1×10⁶) CFU of virulent M.tuberculosis H37Rv.Spleen and the left lung were harvested from each mouse 4 weeks after（infection） and homogenized in sterile saline.Serial dilutions of organ homogenates were plated on （L-J agar） and incubated（37 ℃） until colonies were visible 4 weeks later. Protective efficacy in each experiment was expressed as（reduced） CFU and was compared with the negative control group.The right lung was obtained from each mouse and（inflated） with and stored in 10% formalin saline immediately.Tissues were embedded in paraffin,sec-tioned（and stained） with hematoxylin and eosin.Results MS gene vaccine induced the secretion of more of Th1 cytokines（IFN-γand IL-2）,but not IL-4 and enhanced CTL activity while BCG induced the secretion of both types of cytokines（IFN-γ,IL-2 and IL-4）.Mice immunized with MS gene vaccine had fewer and smaller tubercles than those immunized with PBS or control plasmid DNA,but had more tubercles than the mice inoculated with BCG.Virable bacterial counts in the lungs and spleens of mice receiving DNA encoding MS were reduced as compared with mice injected with PBS or control plasmid DNA,while increased as compared with mice immunized with BCG.Conclusion MS gene vaccine can induce secretion of Th1 cytokines and the higher protective efficacy against TB in mice.更多还原