人IL-12基因表达对含信号肽mtb8.4基因疫苗的免疫效应

EFFECT OF IMMUNITY INDUCED BY CO-IMMUNIZATION OF mtb8.4 GENETIC VACCINE WITH SIGNAL SEQUENCE AND HUMAN INTERLEUKIN 12

[目的]观察结核分枝杆菌含信号肽Mtb8.4(MS)基因疫苗与人白细胞介素12(hIL-12)表达质粒联合免疫小鼠所诱导的细胞免疫应答。[方法]15只C57BL/6N小鼠随机分为MS基因疫苗+hIL-12质粒组(联合免疫组)、MS基因疫苗组、卡介苗(BCG)组、空载体组和PBS组,基因疫苗、空载体和PBS经肌内注射法免疫各组小鼠,每隔3周免疫1次,共免疫3次,BCG组经尾部皮下注射1×106 CFU BCG免疫1次。采用酶联免疫吸附法(ELISA)检测小鼠脾细胞培养上清中细胞因子水平;采用乳酸脱氢酶(LDH)释放法检测免疫小鼠细胞毒性T细胞(CTL)杀伤活性。[结果]联合免疫组能诱导较强的抗原特异性Th1型细胞免疫应答,免疫小鼠脾细胞培养上清液IFN-γ和IL-2水平(分别为(1546.18±36.23)pg/ml、(681.64±40.88)pg/ml),显著高于MS基因疫苗组,与BCG组相当,IL-4分泌减少,特异性CTL杀伤活性增强。[结论]hIL-12表达质粒与MS基因疫苗联合免疫后,能够增强MS基因疫苗所诱导的细胞免疫应答。

[Objective] To observe the specific celluar immune response in mice induced by co-immunization of DNA vaccine of Mth8.4 with signal sequence （MS） and plasmid encoding human interleukin 12 （hIL-12） . [Methods] Fifteen C57BL/6N mice were divided into following groups： MS gene vaccine plus plasmid of hIL-12, MS gene vaccine, BCG, vacant vector alone and PBS. Mice were immunized intramuscularly in both hind limbs three times at the intervals of three weeks or once subcutaneously with 1×10^6 of viable M. bovis BCG Pasteur at the time of the first DNA immunization. The level of IFN-γ in supernatant of spleno-lymphocyte cultures were measured by ELISA methods. CTL activities of spleno-lymphocyte were detected with LDH release assay. The levels of IFN-γ and IL-2 in supernatant of spleno-lymphocyte Cultures in the group of MS gene vaccine plus plasmid of hlL-12 were significantly higher than group of MS alone （P 〈 0. 01 ） and were same as BCG group, the level of IL-4 was lower than BCG group （P 〈 0. 01 ） . CTL activity of spleno-lympbocyte in the co-immtmization group was stronger than other groups. [Conclusion] Co-immunization of MS gene vaccine and plasmid encoding human interleukin 12 can enhance the specific cellular immtme response induced by the MS gene vaccine alone.