弓形虫亲环蛋白亚单位疫苗的免疫保护性研究

Studies on immuno-protection from a Toxoplasma gondii infection provided by a TgCyP subunit vaccine

目的研究弓形虫亲环蛋白(Cyclophilin,CyP)亚单位疫苗的免疫保护性。方法 30只BALB/c小鼠随机分为3组:实验组、佐剂组和PBS对照组,分别肌注pET-28a-TgCyP重组蛋白100μg/只、佐剂100 ul/只和PBS 100 ul/只,共免疫3次,每次间隔2周。末次免疫后2周,各组分别取4只小鼠处死,取脾脏,检测CD4+、CD8+及细胞因子。同时,采用阿尔玛蓝细胞增殖与细胞毒性检测试剂测定小鼠脾淋巴细胞的增殖应答。其余小鼠腹腔攻击感染Rh株弓形虫速殖子500个,观察其存活情况。结果 pET-28a-TgCyP重组蛋白亚单位疫苗能诱发小鼠产生细胞免疫和体液免疫反应,小鼠的CD4+T细胞(62.59±4.17)%、CD8+T细胞(8.53±0.46)%与PBS及佐剂对照组比较显著增殖(P<0.01),其脾细胞培养液白细胞介素-2(IL-2)、γ干扰素(IFN-γ)显著升高,小鼠脾淋巴细胞增殖应答显著增强(P<0.01)。弓形虫攻击感染216 h后,实验组小鼠免疫保护率为33.3%,佐剂对照组及PBS对照组小鼠均全部死亡。结论 pET-28a-TgCyP重组蛋白亚单位疫苗具有较强的免疫原性,能产生良好的免疫保护作用。

Objective To study the protection from Toxoplasma gondii infection provided by a TgCyP subunit vaccine.Methods Thirty BALB/c mice were divided into three groups.Each mouse in the experimental group was injected through the quadriceps femoris muscle with 100 μg recombinant proteins pET-28a-TgCyP.Mice in the adjuvant group were injected with 100 ul adjuvant and those in the control group were injected with 100 ul PBS.All mice were immunized three times at an interval of two weeks.Spleens of 4 mice in each group were removed to detect CD4＋T and CD8＋T cells and cytokines 2 weeks after final immunization.At the same time,the proliferative response of splenic lymphocytes from the tested mice was tested with Alamar Blue reagent.The remaining mice in the 3 groups were challenged with 500 tachyzoites of the T.gondii Rh strain and observed.Results The vaccine induced a strong cellular and humoral immune response.Recombinant protein pET-28a-TgCyP inoculation resulted in a high titer of antibody in serum.The lymphocyte phenotype was analyzed.CD4＋T cells and CD8＋T cells proliferated markedly（62.5966±4.1743% and 8.5367±0.4668%）（P0.01）.The level of IL-2 and IFN-γ in cultured supernatant of spleen cells was higher in the experimental group than in the adjuvant and control groups.The proliferative response of splenic lymphocytes from mice increased sharply（P0.01）.Of mice in the experimental group,33.3% were protected 216 hours after the challenge with T.gondii.All mice in the adjuvant and control groups died.Conclusion The recombinant protein pET-28a-TgCyP subunit vaccine has substantial immunogenicity and provides satisfactory immuno-protection.