In order to observe the effects of different virulent strains of Toxoplasma gondii excretory-secretory antigens ( ESA ) on murine NK cells, 18 C57BL/6J mice were used and treated with 200 jxL different strains of T. gondii ESA ( containing ESA 0. 002 nig) or PBS, respectively. The numbers of splenic NK cells in splenocytes were measured by flow cytometry. Cytotoxicity of NK cells on YAC-1 cells were detected by LDH method. The IFN-7 levels in serum were also tested by ELISA. The result showed that the numbers of NK cells in either RH ESA or PRU ESA treated groups were increased significantly compared with that of PBS control ( 3. 08 ±0. 39 )% ( P < 0. 001 ). In addition, the increasement in RH ESA treated group ( 5. 97 ±0. 26 )% was higher than that in PRU ESA treated group ( 3. 32 ± 0. 29 )% , and the difference is of statistic significance ( P < 0. 001 ). The cytotoxic effects of NK cells on YAC-1 cells in both RH ESA and PRU ESA treated groups were increased obviously compared with that of PBS control ( P < 0. 01 ). The levels of sera IFN-7 in both RH ESA and PRU ESA treated groups were increased significantly compared with that of PBS control ( P < 0. 01 ). Also, the increasement in RH ESA treated group was higher than that in PRU ESA treated group, and the difference is of statistic significance ( P < 0. 05 ). The results suggested that T. gondii ESA could activate NK cells and the efficiency of RH ESA was higher than that of PRU ESA.%为观察不同毒力株弓形虫排泄分泌抗原(Excretory-Secretory antigen,ESA)对小鼠NK细胞的作用,将18只雌性C57BL/6J小鼠随机分为3组,各组每鼠分别腹腔注射刚地弓形虫RH株ESA 200 μL(含ESA 0.002 mg),PRU株ESA 200 μL(含ESA 0.002 mg)和PBS 200 μL.于注射后6天取脾,流式细胞仪检测脾脏NK细胞的比例,并用乳酸脱氢酶(Lactate dehydrogenase,LDH )法检测各组NK细胞的杀伤活性,ELISA检测血清IFN-γ水平.结果显示,RH株ESA处理组NK细胞比例(5.97±0.26)%,PRU株ESA处理组NK细胞比例(3.32±0.29)%,两组均明显高于PBS对照组(3.08±0.39)%(P<0.001),其中RH株ESA处理组明显高于PRU株ESA处理组,差异有统计学意义(P<0.001);不同毒力株ESA处理的小鼠NK细胞杀伤能力较对照组有明显的升高,3组间差异有统计学意义(P<0.01);不同毒力株ESA处理后小鼠血清的IFN-γ水平升高,与PBS组相比差异有统计学意义(P<0.01),其中RH组小鼠血清中IFN-γ浓度较PRU组升高更为明显,差异存在统计学意义(P<0.05).结果表明,弓形虫ESA有活化小鼠NK细胞的作用,且RH株ESA的作用强于PRU株ESA.
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