Sharma S D, Verhoef J, Remington J S
Cell Immunol. 1984 Jul;86(2):317-26. doi: 10.1016/0008-8749(84)90386-1.
The ability of sonicates and subcellular fractions of the intracellular parasite Toxoplasma gondii to enhance in vitro human natural killer (NK) cell activity was examined. Incubation of nylon-wool-non-adherent human peripheral blood lymphocytes (PBL) with sonicates of T. gondii for 18-72 hr resulted in increased NK activity against an NK-sensitive, as well as an insensitive, target cell. Single-cell assays revealed that augmentation of NK activity was not due to an increased binding of K562 target cells to effector cells. Differential centrifugation studies indicated that NK-augmenting activity was distributed in membrane-enriched and cytoplasmic fractions. This activity was found to be resistant to treatment with ribonuclease (RNase) and deoxyribonuclease (DNase), but susceptible to proteolysis. Antibodies present in the serum of humans infected with Toxoplasma blocked the NK cell-augmenting effect of the membrane-enriched fractions. Enhancement of NK activity by PBL incubated with Toxoplasma sonicate was accompanied by a concomitant increase in interferon (IFN), but not of interleukin 2 (IL-2), levels in supernatants of the cell cultures.
对细胞内寄生虫刚地弓形虫的超声裂解物和亚细胞组分增强体外人自然杀伤（NK）细胞活性的能力进行了检测。用刚地弓形虫超声裂解物孵育尼龙毛非黏附人外周血淋巴细胞（PBL）18 - 72小时，导致对NK敏感以及不敏感靶细胞的NK活性增加。单细胞分析显示，NK活性的增强并非由于K562靶细胞与效应细胞结合增加所致。差速离心研究表明，NK增强活性分布于富含膜的组分和细胞质组分中。发现该活性对核糖核酸酶（RNase）和脱氧核糖核酸酶（DNase）处理具有抗性，但对蛋白水解敏感。感染弓形虫的人血清中的抗体可阻断富含膜组分的NK细胞增强效应。用弓形虫超声裂解物孵育的PBL增强NK活性的同时，细胞培养上清液中的干扰素（IFN）水平随之升高，但白细胞介素2（IL - 2）水平未升高。
