Specific binding by human polymorphonuclear leucocytes of the immunological mediator 1-O-hexadecyl/octadecyl-2-acetyl-sn-glycero-3-phosphorylcholine.
Specific binding by human polymorphonuclear leucocytes of the immunological mediator 1-O-hexadecyl/octadecyl-2-acetyl-sn-glycero-3-phosphorylcholine.
复制标题
人多形核白细胞与免疫介质 1-O-十六烷基/十八烷基-2-乙酰基-sn-甘油-3-磷酸胆碱的特异性结合。
作者：
F. Valone;E. Goetzl
人多形核白细胞与血小板活化因子1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphorylcholine(AGEPC)的结合在20-30分钟内即可完成，最适温度为37度。Scatchard图分析了未标记AGEPC和过量AGEPC的PMN白细胞与[~3H]AGEPC的总结合，揭示了两种不同类型的结合位点。其中一种结合位点具高亲和力(Kd=0.11+/-0.02 nM，Mean+/-SD)，是饱和的，最大容量为5.2+/-2.1×10(6)(Mean+/-SD)分子/PMN白细胞。另一个结合部位表现出显著较低的结合亲和力和较大的结合能力，与AGEPC对细胞结构的非受体摄取一致。在改良的Boyden小室中，悬液中PMN白细胞的高亲和力结合部位饱和于AGEPC的196+/-90pmoL(平均值+/-SD)，而600pmoL/mlAGEPC在改良的Boyden小室中引起最大的PMN白细胞趋化。AGEPC与中性粒细胞结合的特异性是通过AGEPC类似物抑制[~3H]AGEPC结合的能力而不是结构上不同的趋化因子来确定的。中性粒细胞与AGEPC的高亲和力结合部位是α-醚键磷脂和β-短链脂肪酸的专一性结合部位，但缺乏立体特异性。类似的结构要求是立体特异性。AGEPC对中性粒细胞趋化作用的诱导和对中性粒细胞C3b受体表达的增强也有相似的结构要求。
The binding of the platelet-activating factor 1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphorylcholine (AGEPC) by human polymorphonuclear (PMN) leucocytes was complete within 20-30 min and optimal at 37 degrees. Scatchard plot analyses of the total binding of [3H]AGEPC by PMN leucocytes without and with an excess of unlabelled AGEPC revealed two distinct types of binding sites. One type of binding site exhibited a high affinity (KD = 0.11 +/- 0.02 nM, mean +/- SD), was saturable and had a maximal capacity of 5.2 +/- 2.1 x 10(6) (mean +/- SD) molecules of AGEPC per PMN leucocyte. The other binding site demonstrated a substantially lower binding affinity and a greater binding capacity consistent with nonreceptor uptake of AGEPC into cellular structures. The high affinity binding site of PMN leucocytes in suspension was saturated at 196 +/- 90 pmol (mean +/- SD) of AGEPC per ml, while 600 pmol of AGEPC per ml evoked maximal PMN leucocyte chemotaxis in modified Boyden chambers. The specificity of binding of AGEPC by PMN leucocytes was established by the capacity of analogues of AGEPC, but not structurally distinct chemotactic factors, to inhibit the binding of [3H]AGEPC. The high affinity PMN leucocyte binding site for AGEPC was specific for a phospholipid with an alpha-ether linkage and a beta-short chain fatty acid, but the binding site lacked stereospecificity. Similar structural requirements were stereospecificity. Similar structural requirements were observed for the elicitation of PMN leucocyte chemotaxis and the enhancement of the expression of PMN leucocyte C3b receptors by AGEPC.