弓形虫P30乳酸球菌口服免疫小鼠适当免疫剂量的探讨

Evaluation of the optimum immune dose for recombinant Lactococcus lactis ex-pressing P30 of Toxoplasma gondii orally immunized to mice

目的:探讨弓形虫P30乳酸球菌口服免疫小鼠的适当免疫剂量,为体内免疫活性的研究提供直接的实验数据。方法:用弓形虫P30乳酸球菌口服免疫BALB/c实验小鼠,设三个免疫剂量组,分别为3×109CFU、3×108CFU、3×107CFU,同时设生理盐水对照组。免疫结束2w后,各实验组分别收集小鼠血清,以ELISA法测定血清中特异性抗体IgG的含量;各实验组取5只小鼠,以100个弓形虫强毒力RH株速殖子做虫体攻击实验,记录死亡时间。结果:三个免疫剂量组,在小鼠体内产生的抗体IgG有一定的差异(P<0.01),但免疫剂量组一(3×109CFU)与免疫剂量组2(3×108CFU)几乎没有差别,免疫剂量组二偏差稍大;免疫剂量组一小鼠的平均存活时间有所延长,免疫剂量组二的小鼠最先出现死亡现象。结论:确定了3×109CFU的免疫剂量,在此剂量下,小鼠的保护性效果则比其他剂量组有所提高。

Objective：To evaluate the optimum immune dose for recombinant Lactococcus lactis expressing P30 of Toxoplasma gondii orally immunized to mice. Methods：Three different immune dose 3×10^9 CFU, 3×10^8CFU and 3×10^7CFU of recombinant L.lactis/P30 were administered orally to BALB/c mice. Control group was orally administered with normal saline. At the second week after immunization, sera from all animals were collected and tested with ELISA for the presence of total antibodies IgG, and then mice of each group were challenged with 100 tachyzoites of the RH strain of T. gondii. Results：There were some differences for antibody IgG in mice orally immunized with three different immune dose of L.lactis/ P30（P〈0.01）. Mean survival time of group 1 with immune does 3×10^9 CFU was longer than that of the other groups, and the mice of group 2 with immune dose 3×10^8CFU were died at first. Conclusion：3×10^9 CFU immune dose is selected. The mice immunized with the selected immune dose generate a distinct immunoprotection compared with the mice immunized with the other immune dose.