Mizutani Y, Nio Y, Yoshida O
Department of Urology, Faculty of Medicine, Kyoto University, Japan.
J Urol. 1992 Nov;148(5):1571-6. doi: 10.1016/s0022-5347(17)36972-0.
Our previous studies have indicated that the protein-bound polysaccharide Kreha (PSK) enhances the cytotoxic activity of peripheral blood lymphocytes (PBL) against the T24 human urinary bladder tumor cell line in patients with bladder tumor. Since PSK consists of a mixture of various kinds of protein-bound polysaccharides, the present study was designed to examine which subfractions of PSK mediated the enhancement of cytotoxicity. When PSK was separated according to size, treatment of PBL with the 50 kilodalton (kd) or less fraction killed T24 cells more efficiently than unfractionated PSK-treated PBL. The higher molecular weight fractions did not enhance killing above the control level. PSK was fractionated on a diethylaminoethyl (DEAE)-cellulose column to obtain a protein rich fraction that absorbed onto the column and a polysaccharide rich fraction that did not. PBL treated with the polysaccharide rich fraction were able to kill T24 cells more effectively than unfractionated PSK-treated PBL. The protein rich fraction had no effect on the killing. Further fractionation of the polysaccharide rich fraction was performed by differential precipitation with ammonium sulfate. PBL treated with the precipitated fraction at 70-80% saturation (PSK Fraction D) enhanced cytotoxicity equal to that of the polysaccharide rich fraction. Treatment of PBL with the other fractions did not augment the cytotoxicity. These enhancement by PSK fractions were observed in healthy donors and also in patients with bladder tumor. An increase of the proliferative response of PBL to PSK Fraction D as well as unfractionated PSK was observed. Treatment of PBL with PSK Fraction D had no effect on the proportion of PBL binding to T24 cells, thus suggesting a post-binding effect. The structure of PSK Fraction D as inferred from the results of methylation analysis was mainly an alpha-glucan. These results demonstrate that PSK mediated enhancement of cytotoxicity and proliferation of PBL may be largely due to an alpha-glucan of less than 50 kd.
我们之前的研究表明，蛋白结合多糖Kreha（PSK）可增强膀胱癌患者外周血淋巴细胞（PBL）对T24人膀胱肿瘤细胞系的细胞毒活性。由于PSK由多种蛋白结合多糖混合而成，本研究旨在检测PSK的哪些亚组分介导了细胞毒性的增强。当根据大小对PSK进行分离时，用50千道尔顿（kd）及以下组分处理PBL比用未分级的PSK处理的PBL更有效地杀死T24细胞。较高分子量的组分在对照水平以上并未增强杀伤作用。将PSK在二乙氨基乙基（DEAE）-纤维素柱上进行分级分离，以获得吸附在柱上的富含蛋白质的组分和未吸附的富含多糖的组分。用富含多糖的组分处理的PBL比用未分级的PSK处理的PBL更有效地杀死T24细胞。富含蛋白质的组分对杀伤作用没有影响。通过硫酸铵分级沉淀对富含多糖的组分进行进一步分级。用饱和度为70-80%的沉淀组分（PSK组分D）处理PBL可增强细胞毒性，其程度与富含多糖的组分相同。用其他组分处理PBL并未增强细胞毒性。在健康供体以及膀胱癌患者中均观察到PSK组分的这些增强作用。观察到PBL对PSK组分D以及未分级的PSK的增殖反应增加。用PSK组分D处理PBL对PBL与T24细胞结合的比例没有影响，因此提示为结合后效应。从甲基化分析结果推断，PSK组分D的结构主要是α-葡聚糖。这些结果表明，PSK介导的PBL细胞毒性增强和增殖可能主要归因于小于50 kd的α-葡聚糖。
