Morita Yuki, Wang Rong, Li Xuyang, Muramatsu Tomonari, Ueda Masumi, Hachimura Satoshi, Takahashi Sachiko, Miyakawa Takuya, Tanokura Masaru
Laboratory of Basic Science on Healthy Longevity, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan; Medical Viara, 5-19 Akashi-cho, Chuo-ku, Tokyo, 104-0044, Japan; MAF Clinic, 5-19 Akashi-cho, Chuo-ku, Tokyo, 104-0044, Japan.
Laboratory of Basic Science on Healthy Longevity, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan; Research Center for Food Safety, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
Protein Expr Purif. 2020 Nov;175:105714. doi: 10.1016/j.pep.2020.105714. Epub 2020 Jul 29.
Cancer immunotherapy has recently attracted attention as an approach for cancer treatment through the activation of the immune system. Group-specific component (Gc) protein is a precursor for macrophage activating factor (GcMAF), which has a promising immunomodulatory effect on the suppression of tumor growth and angiogenesis. In this study, we successfully purified Gc protein from human serum using anion-exchange chromatography combined with affinity chromatography using a 25-OH-D-immobilized column. The purity of Gc protein reached 95.0% after anion-exchange chromatography. The known allelic variants of Gc protein are classified into three subtypes-Gc1F, Gc1S and Gc2. The fragment sequence of residues 412-424 determined according to their MS/MS spectra is available to evaluate the subtypes of Gc protein. The data showed that the Gc protein purified in this study consisted of the Gc1F and Gc2 subtypes. Our method improved the purity of Gc protein, which was not affected by the treatment to convert it into GcMAF using β-galactosidase- or neuraminidase-immobilized resin, and will be useful for biological studies and/or advanced clinical uses of GcMAF, such as cancer immunotherapy.
癌症免疫疗法作为一种通过激活免疫系统来治疗癌症的方法，最近受到了关注。群特异性成分（Gc）蛋白是巨噬细胞激活因子（GcMAF）的前体，GcMAF对抑制肿瘤生长和血管生成具有有前景的免疫调节作用。在本研究中，我们使用阴离子交换色谱结合使用固定有25-羟基-D的柱的亲和色谱，成功地从人血清中纯化了Gc蛋白。阴离子交换色谱后，Gc蛋白的纯度达到95.0%。Gc蛋白的已知等位基因变体分为三种亚型——Gc1F、Gc1S和Gc2。根据其MS/MS谱确定的412-424位残基的片段序列可用于评估Gc蛋白的亚型。数据表明，本研究中纯化的Gc蛋白由Gc1F和Gc2亚型组成。我们的方法提高了Gc蛋白的纯度，该纯度不受使用固定有β-半乳糖苷酶或神经氨酸酶的树脂将其转化为GcMAF的处理的影响，并且将对GcMAF的生物学研究和/或高级临床应用（如癌症免疫疗法）有用。
