This study characterized the activation of platelet integrin α bβ3 induced by two anti human platelet tetraspanin monoclonal antibodies(mAbs),HI117 and SJ9A4. Methods.Using 125 I labeled human fibrinogen(Fg),specifi...This study characterized the activation of platelet integrin α bβ3 induced by two anti human platelet tetraspanin monoclonal antibodies(mAbs),HI117 and SJ9A4. Methods.Using 125 I labeled human fibrinogen(Fg),specific Fg binding to human platelets induced by HI117 and SJ9A4 was measured as indication of activation of platelet integrin αbβ3 by the two mAbs. Results.HI117 and SJ9A4(10μg/ml and 20μg/ml) induced evident specific Fg binding to human platelets,suggesting that the two mAbs evoked activation of platelet integrin αbβ3.Further study indicated that HI117 and SJ9A4 induced integrin αⅡbβ3 activation independent of platelet Fc receptors, and that HI117 and SJ9A4 induced integrin αbβ3 activation was inhibited by sphingosing, aspirin, apyrase, and/or PGI2. Conclusion.The anti platelet tetraspanin(CD9)mAbs,HI117 and SJ9A4, can induce platelet integrin αⅡbβ3 activation independent of Fc receptors.Three signaling pathways,i.e.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.展开更多
文摘This study characterized the activation of platelet integrin α bβ3 induced by two anti human platelet tetraspanin monoclonal antibodies(mAbs),HI117 and SJ9A4. Methods.Using 125 I labeled human fibrinogen(Fg),specific Fg binding to human platelets induced by HI117 and SJ9A4 was measured as indication of activation of platelet integrin αbβ3 by the two mAbs. Results.HI117 and SJ9A4(10μg/ml and 20μg/ml) induced evident specific Fg binding to human platelets,suggesting that the two mAbs evoked activation of platelet integrin αbβ3.Further study indicated that HI117 and SJ9A4 induced integrin αⅡbβ3 activation independent of platelet Fc receptors, and that HI117 and SJ9A4 induced integrin αbβ3 activation was inhibited by sphingosing, aspirin, apyrase, and/or PGI2. Conclusion.The anti platelet tetraspanin(CD9)mAbs,HI117 and SJ9A4, can induce platelet integrin αⅡbβ3 activation independent of Fc receptors.Three signaling pathways,i.e.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.
