Czop J K, Austen K F
J Immunol. 1985 Apr;134(4):2588-93.
The ligand specificity of the human monocyte receptor that mediates phagocytosis of particulate activators of the human alternative complement pathway was defined by inhibiting the phagocytic response with glycans known to be present in zymosan. When monocytes in monolayers were preincubated with 100 micrograms/ml of beta-glucan and then incubated with 1.25 to 2.5 X 10(6) zymosan particles, the percentage of cells that exhibited phagocytosis was inhibited in a time-dependent manner; maximal inhibition occurred within 20 min of preincubation. beta-Glucan inhibited monocyte phagocytosis of zymosan and rabbit erythrocytes (Er) in a similar dose-dependent fashion and at 100 micrograms/ml reduced monocyte ingestion of 5 X 10(6)/ml zymosan and 2 X 10(8)/ml Er by 63 +/- 8% and 68 +/- 16% (mean +/- SD, n = 3), respectively. The other glycan constituent of zymosan, mannan, was less than 1% as active, and 10 mg/ml of mannan reduced the number of monocytes ingesting zymosan and Er by 56 +/- 12% and 26 +/- 11%, respectively. At concentrations as high as 500 micrograms/ml, beta-glucan had no effect on monocyte Fc, C3b, or fibronectin receptor-mediated functions. Enzymatic hydrolysis of beta-glucan and alpha-mannan with beta-glucosidase or beta-glucanase before their incubation with monocytes abrogated their inhibitory capacity, whereas hydrolysis with alpha-mannosidase or alpha-glucosidase did not. Neither of the two alpha-glucans tested (dextran T-70 and nigeran) affected monocyte ingestion of zymosan particles or sheep erythrocytes (Es) sensitized with rabbit 7S anti-Es (EsIgG) at concentrations as high as 2 mg/ml. In contrast, a number of beta-glucans were active against zymosan but not EsIgG ingestion with a 75% reduction in the number of monocytes ingesting zymosan occurring with 100 micrograms/ml laminarin, 500 micrograms/ml soluble pachyman, and 900 micrograms/ml of soluble pustulan. The galactan, agarose, either in suspensions at 2 mg/ml or in a soluble portion at 600 micrograms/ml failed to affect monocyte ingestion of zymosan particles or Er. Thus, the monocyte receptor for particulate activators that is specifically inhibited by beta-glucan at a rate compatible with a phagocytic process and that recognizes beta-glucans but not alpha-glucans, mannan, or galactan is a beta-glucan receptor.
通过用已知存在于酵母聚糖中的聚糖抑制吞噬反应，确定了介导人替代补体途径颗粒激活剂吞噬作用的人单核细胞受体的配体特异性。当单层培养的单核细胞与100微克/毫升的β-葡聚糖预孵育，然后与1.25至2.5×10⁶个酵母聚糖颗粒孵育时，表现出吞噬作用的细胞百分比呈时间依赖性抑制；预孵育20分钟内出现最大抑制。β-葡聚糖以类似的剂量依赖性方式抑制单核细胞对酵母聚糖和兔红细胞（Er）的吞噬作用，在100微克/毫升时，单核细胞对5×10⁶/毫升酵母聚糖和2×10⁸/毫升Er的摄取分别减少63±8%和68±16%（平均值±标准差，n = 3）。酵母聚糖的另一种聚糖成分甘露聚糖的活性不到1%，10毫克/毫升的甘露聚糖分别使摄取酵母聚糖和Er的单核细胞数量减少56±12%和26±11%。在高达500微克/毫升的浓度下，β-葡聚糖对单核细胞Fc、C3b或纤连蛋白受体介导的功能没有影响。β-葡聚糖和α-甘露聚糖在与单核细胞孵育前用β-葡萄糖苷酶或β-葡聚糖酶进行酶水解消除了它们的抑制能力，而用α-甘露糖苷酶或α-葡萄糖苷酶水解则没有。所测试的两种α-葡聚糖（葡聚糖T-70和黑曲霉聚糖）在高达2毫克/毫升的浓度下均不影响单核细胞对酵母聚糖颗粒或用兔7S抗-Es（EsIgG）致敏的绵羊红细胞（Es）的摄取。相反，一些β-葡聚糖对酵母聚糖有活性，但对EsIgG摄取无活性，100微克/毫升海带多糖、500微克/毫升可溶性茯苓聚糖和900微克/毫升可溶性支链淀粉使摄取酵母聚糖的单核细胞数量减少75%。2毫克/毫升悬浮液或600微克/毫升可溶部分的半乳聚糖琼脂糖均不影响单核细胞对酵母聚糖颗粒或Er的摄取。因此，被β-葡聚糖以与吞噬过程相容的速率特异性抑制且识别β-葡聚糖但不识别α-葡聚糖、甘露聚糖或半乳聚糖的颗粒激活剂的单核细胞受体是β-葡聚糖受体。
