重组卡介苗和传统卡介苗免疫原性的比较

目的 观察分泌人白细胞介素(IL)-2的重组卡介苗(rBCG)和传统卡介苗(BCG)对小鼠免疫应答的影响,评价其免疫原性,初步探讨rBCG免疫治疗的作用机制.方法 连续6周对BALB/C小鼠尾静脉注射rBCG和BCG,分别在第2、4和6周后杀死小鼠取腹腔巨噬细胞和脾脏.以一氧化氮(NO)释放量检测巨噬细胞吞噬活性,以淋巴细胞刺激指数(SI)反映细胞增殖能力,以流式细胞仪测定T淋巴细胞CD亚群分化和酶联免疫吸附试验(ELISA)法检测小鼠脾淋巴细胞培养上清细胞因子分泌的变化,比较rBCG治疗组和BCG治疗组之间的差异.结果 在连续6周观察期间,随着免疫时间的延长,rBCG对小鼠脾脏T淋巴细胞的增殖能力逐渐增强,CD4+、CD8+T细胞和CD4+/CD8+的比例逐渐增高,腹腔巨噬细胞的吞噬活性逐渐增高,诱导小鼠脾淋巴细胞分泌的Th1型和Th2型细胞因子逐渐增多.在同一时点上,不同rBCG和BCG的上述作用均高于空白对照组(P均0.01),差异有统计学意义;rBCG治疗组的上述作用均高于BCG治疗组.结论 rBCG具有良好的免疫原性,能明显增强BALB/c小鼠的免疫应答反应.rBCG诱导的T细胞免疫应答主要是CD4+T细胞依赖的,CD4+细胞免疫应答主要是以Th1型细胞因子参与为主,Th2型细胞因子也发挥一定作用.

Comparative study on immunogenidty of recombinant BCG vs BCG

Objective To compare the immunogenicity of recombinant BCG (rBCG) secreting interleukin-2 (IL-2) and BCG, and investigate the mechanism of immunotherapeutic effect on BALB/c Mice.Methods Mimieing the standard BCG instillation schedule, BALB/c mice were inoculated intrave-nously through the lateral tail vein 5 x 105 colony forming units (CFU) of rBCG stmin comparing with 1 x106 CFU of BCG and PBS weekly for 6 weeks.MTr assay was used to confirm the effect of rBCG on indue-tion of macrophage activity and proliferation of T lymphocyte.The changes of CD4+ and CD8 + subsets were examined by flow eytometry.Thl cytokines (IL-2 and IFN-γ) and Th2 cytokine (IL-4) in the cul-ture supematant of mice spleen lymphocytes were detected by an enzyme-linked immunosorbent assay (ELBA) after 2,4 and 6 successive weekly BCG instillations.Results During 6 weekly BCG strain and rBCG inoculation a time-dependent induction of the T lymphocyte proliferation, CD subsets, macrophage activity and cytokines (including IL-2, IL-4 and IFN-γ) was observed.At the different time points, there was significant difference between the rBCG therapy group and BCG therapy group or control group.Con-clusion Recombinant BCG strain enhanced immunostimulatory potential in BALB/c mice and could ef-fectively induce specific stronger immune response in BALB/c mice than BCG did.This immune reaction induced by rBCG was CD4+ T eell-depent and defined as a major Thl accompanied by a minor Th2 re-sponse.