摘要目的研究2种抗人血小板tetraspanin单克隆抗体HI117和SJ9A4引起的血小板整合素活化及其机制。方法用125 Ⅰ标记的人纤维蛋白原，测定HI117和SJ9A4引起的纤维蛋白原与人血小板的特异的结合，表明这2种单抗激活血小板整合素αⅡbβ3。结果 HI117和SJ9A4(10?μg/ml和20?μg/ml)引起纤维蛋白原与人血小板特异的结合，表明这2种单抗引起血小板整合素αⅡbβ3激活，进一步研究表明这种激活不依赖血小板Fc受体，而且HI117和SJ9A4引起的血小板整合素αⅡbβ3激活可由于以Sphingosine、Aspirin、αβ、rase和成PGI2预处理血小板而被抑制。结论抗人血小板tetraspanin (CD9)单克隆抗体HI117和SJ9A4能引起血小板整合素αⅡbβ3激活且不依赖Fc受体，3种信号途径即血栓烷，分泌ADP和CAMP途径可能涉及这一过程，蛋白激酶C激活可能是这3个途径的共同步骤。

abstractsObjectives　To characterize the activation of platelet integrin αⅡbβ3 induced by two anti-human platelet tetraspanin monoclonal antibodies (mAbs), HI117 and SJ9A4, and investigate their potential mechanism of action. Methods　Using 125　　I-labeled human fibrinogen (Fg), specific Fg binding to human platelets induced by HI117 and SJ9A4 was measured.Results　HI117 and SJ9A4 (10?μg/ml and 20?μg/ml) induced specific Fg binding to human platelets, suggesting that the two mAbs evoked activation of platelet integrin αⅡbβ3. Further study indicated that HI117 and SJ9A4 induced integrin αⅡbβ3 activation independent of platelet Fc-receptors, and that HI117 and SJ9A4-induced integrin αⅡbβ3 activation was inhibited by pretreatment of platelets with sphingosine, aspirin, apyrase, and/or PGI2. Conclusions　Anti-platelet tetraspanin (CD9) mAbs, HI117 and SJ9A4, can induce platelet integrin αⅡbβ3 activation independent of Fc-receptors. Three signaling pathways, namely thromboxane, secreted ADP, and cAMP pathways, may be involved in the process, with protein kinase C activation presumably being the common step of the three pathways.