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目的 对血小板活化过程中膜糖蛋白（ Ｇ Ｐ） Ⅱｂ／ Ⅲａ 构象变化进行初步探讨。方法 分别用供体荧光（ Ｆ Ｉ Ｔ Ｃ） 与受体荧光（ Ｔ Ｒ） 标记识别 Ｇ ＰⅡｂ／ Ⅲａ 上不同抗原决定簇的单抗。用流式细胞仪检测活化血小板在５３０ ｎｍ 处的荧光强度值，并计算荧光供受体间的荧光共振能量转移值（ Ｆ Ｒ Ｅ Ｔ Ｖ） 。结果 不论何种单抗作为荧光供体，静息态血小板均可被测得一低而稳定的 Ｆ Ｒ Ｅ Ｔ Ｖ（ 平均５ ．５ ％ ） 。血小板被激活时 Ｆ Ｒ Ｅ Ｔ Ｖ 会有显著升高，表明 Ｇ ＰⅡｂ／ Ⅲａ 内的亚单位间发生了位置或（ 和） 方向上的变化，该变化也可因胞外钙离子的清除而发生，但不依赖于纤维蛋白原与其受体的结合。结论 血小板活化时 Ｆ Ｒ Ｅ Ｔ Ｖ 的升高可定性反映出荧光标记单抗所结合的 Ｇ ＰⅡｂ／ Ⅲａ 内部亚单位间所发生的重新排列，这种构象的改变可最终导致纤维蛋白原受体的表达。
Objective To investigate the conformational changes of membrane glycoprotein (G P) Ⅱb / Ⅲa during platelet activation. Methods The monoclonal antibodies of different epitopes on GpⅡb / Ⅲa were identified by FITC and T R labeling, respectively. The fluorescence intensity of activated platelets at 530 nm was measured by flow cytometry and the fluorescence resonance energy transfer (F R E T V) between fluorescent donor and acceptor was calculated. Results Regardless of which mAb was used as a fluorescent donor, a low and stable F REVE (mean 5.5%) was measured on resting platelets. Platelets are activated when F R E T V will be significantly increased, indicating G P Ⅱ b / Ⅲ a subunits within the location or (direction) of the change, the change may also be due to the removal of extracellular calcium ions occurred , But not on the binding of fibrinogen to its receptor. Conclusions Elevation of F R E T V during platelet activation characteristically reflects the rearrangement of the G P IIb / IIIa internal subunits to which the fluorescently labeled mAb binds. This conformational change can eventually lead to fibrinogen receptor expression.