A not well-appreciated but clinically important aspect of malignant tumours is their effects on distantly located host cells. The effects, termed paraneoplastic syndromes, also pose an intriguing mechanistic problem: how do malignant cells influence properties of host cells not in contact with them? Erythrocytes from the circulation of rats bearing intraperitoneal Yoshida ascites sarcoma exhibit higher agglutinability with concanavalin A (Con A) than the cells from normal animals. Since the tumour and the red cells are not in contact, the enhanced agglutinability of the latter is a paraneoplastic effect. The mechanism by which the tumour brings about this effect is investigated as a model for paraneoplastic syndromes. The cell-free ascites fluid is able to impart high agglutinability on cells from normal animals in vitro. Also, when injected intraperitoneally in normal animals, the ascites fluid is able to enhance the agglutinability of erythrocytes in circulation. Apparently the tumour produces a substance(s) that appears in the ascites fluid and is able to diffuse into circulation, explaining the mechanism by which it can reach distant sites. From the cell-free ascites fluid three fractions have been isolated that are active in vitro. Of these, only one showed activity in vivo. From this fraction, a glycoprotein has been purified to homogeneity that confers maximal Con A-agglutinability on normal erythrocytes at 8 x 10(-7)M, at which concentration 6,400 molecules bind per cell. The protein has a molecular weight of 600 kDa in the native state and a pI of 5.35. It is made up of 4 identical subunits of Mr 170,000. It is detected in the plasma of tumour-bearing but not normal rats.(ABSTRACT TRUNCATED AT 250 WORDS)

译文

恶性肿瘤的一个不被重视但临床上重要的方面是它们对遥远定位的宿主细胞的影响。这种效应被称为副肿瘤综合征,也带来了一个有趣的机制问题: 恶性细胞如何影响不与它们接触的宿主细胞的特性?腹膜内携带吉田腹水肉瘤的大鼠循环中的红细胞与刀豆球蛋白A (Con A) 相比,其凝集性高于正常动物的细胞。由于肿瘤和红细胞不接触,因此后者的凝集能力增强是一种副肿瘤作用。研究了肿瘤引起这种作用的机制,作为副肿瘤综合征的模型。无细胞腹水能够在体外对正常动物的细胞赋予高度凝集性。同样,当在正常动物中腹膜内注射时,腹水能够增强循环中红细胞的凝集能力。显然,肿瘤会产生一种物质,这种物质会出现在腹水中,并能够扩散到循环中,从而解释了它可以到达远处的机制。从无细胞的腹水液中分离出三个在体外具有活性的部分。其中,只有一个在体内显示出活性。从该级分中,糖蛋白已被纯化至同质,其在8 × 10(-7)M的正常红细胞上赋予最大的Con-凝集性,在该浓度下6,400分子结合每个细胞。该蛋白质在天然状态下具有600 kDa的分子量和5.35的pI。它由Mr 170,000的4个相同的亚基组成。它是在荷瘤大鼠的血浆中检测到的,但不是正常大鼠。(摘要截短于250字)

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