Janusz M J, Austen K F, Czop J K
J Immunol. 1986 Nov 15;137(10):3270-6.
The trypsin-sensitive receptor that mediates phagocytosis of unopsonized zymosan particles by human monocytes has been designated as a beta-glucan receptor because of its functional inhibition by specific algal and plant beta-glucans. Soluble ligands that are chemically and structurally identical to beta-glucan constituents of zymosan were isolated from a carbohydrate-enriched fraction of yeast extract by sequential chromatography on DE-cellulose, SP-Sephadex, and Con A-Sepharose. Preincubation of adherent human monocytes with 278, 210, and 2.5 micrograms/ml hexose equivalents in pooled chromatographic fractions from DE-cellulose, SP-Sephadex, and Con A-Sepharose, respectively, effected 50% reductions in subsequent phagocytosis of zymosan particles without affecting Fc-mediated ingestion of IgG-coated sheep erythrocytes (ESIgG). The purified yeast extract-derived beta-glucans, which contained 92% glucose and 8% mannose by gas chromatographic analysis and eluted from a Sephacryl S-200 column as a broad peak with a Kav of 0.39 and estimated molecular sizes of from 20,000 to 70,000 m.w., required only 3.5 +/- 0.9 micrograms/ml (mean +/- SD, n = 6), as compared with 31.5 micrograms/ml of the algal beta-glucan laminarin to achieve 50% decreases in zymosan ingestion. Alternatively, soluble yeast beta-glucans with estimated molecular sizes of from 2 X 10(5) to 2 X 10(6) were prepared from yeast glucan particles, which contained 98% glucose and 0% mannose, by sonication and sequential centrifugation at 15,000 and 100,000 X G for 30 and 60 min, respectively. Monocyte ingestion of zymosan was reduced by 50% by pretreatment with 60 ng/ml of the soluble beta-glucans in 15,000 X G supernatants, whereas ingestion of ESIgG was unaffected by as much as 50 micrograms/ml of this material. Partial acid hydrolysis of soluble glucan-derived beta-glucans in 15,000 X G supernatants followed by gel filtration on Bio-Gel P-4 revealed two well-defined peaks within the inclusion volume of the column with phagocytosis-inhibiting activity. Oligoglucosides that eluted at a Kav of 0.46 had an estimated molecular size of 2,000 m.w. and effected a 48% reduction in zymosan ingestion at inputs of 2 to 5 micrograms/ml, and smaller oligoglucosides with a Kav of 0.82 and an estimated molecular size of 1,000 m.w. effected a 50% reduction at inputs of 25 micrograms/ml. Preincubation of monocytes for 2 min with 25 micrograms/ml of the oligoglucosides with estimated molecular size of 1,000 m.w. and with 50 ng/ml of soluble glucan-derived beta-glucans in 100,000 X G supernatants reduced zymosan ingestion by 41% +/- 4 and 44% +/- 3 (mean +/- SD, n = 3), respectively.(ABSTRACT TRUNCATED AT 400 WORDS)
介导人单核细胞对未调理酵母聚糖颗粒进行吞噬作用的胰蛋白酶敏感受体，因其受特定藻类和植物β-葡聚糖的功能抑制作用，而被指定为β-葡聚糖受体。通过在DE-纤维素、SP-葡聚糖凝胶和刀豆球蛋白A-葡聚糖凝胶上进行连续色谱法，从富含碳水化合物的酵母提取物组分中分离出在化学和结构上与酵母聚糖的β-葡聚糖成分相同的可溶性配体。分别用来自DE-纤维素、SP-葡聚糖凝胶和刀豆球蛋白A-葡聚糖凝胶的合并色谱级分中278、210和2.5微克/毫升己糖当量对贴壁人单核细胞进行预孵育，可使随后酵母聚糖颗粒的吞噬作用降低50%，而不影响Fc介导的IgG包被绵羊红细胞（ESIgG）的摄取。经气相色谱分析，纯化的酵母提取物衍生的β-葡聚糖含有92%的葡萄糖和8%的甘露糖，从Sephacryl S-200柱上洗脱为一个宽峰，Kav为0.39，估计分子量为20,000至70,000道尔顿，仅需3.5±0.9微克/毫升（平均值±标准差，n = 6），相比之下，藻类β-葡聚糖海带多糖达到酵母聚糖摄取降低50%则需要31.5微克/毫升。或者，通过超声处理并分别在15,000和100,000×G下连续离心30和60分钟，从含有98%葡萄糖和0%甘露糖的酵母葡聚糖颗粒制备估计分子量为2×10⁵至2×10⁶的可溶性酵母β-葡聚糖。用15,000×G上清液中60纳克/毫升的可溶性β-葡聚糖预处理单核细胞，可使酵母聚糖的摄取降低50%，而摄取ESIgG则不受高达50微克/毫升该物质的影响。对15,000×G上清液中可溶性葡聚糖衍生的β-葡聚糖进行部分酸水解，然后在Bio-Gel P-4上进行凝胶过滤，在柱的包容体积内显示出两个具有吞噬抑制活性的明确定义的峰。以Kav 0.46洗脱的低聚糖苷估计分子量为2,000道尔顿，在2至5微克/毫升的输入量下可使酵母聚糖摄取降低48%，而Kav为0.82且估计分子量为1,000道尔顿的较小低聚糖苷在25微克/毫升的输入量下可使摄取降低50%。用估计分子量为1,000道尔顿的25微克/毫升低聚糖苷和100,000×G上清液中50纳克/毫升的可溶性葡聚糖衍生的β-葡聚糖对单核细胞预孵育2分钟，分别使酵母聚糖摄取降低41%±4和44%±3（平均值±标准差，n = 3）。（摘要截断于400字）
