性做久久久久久坡多野结衣-性做久久久久久久久浪潮-性欲影院-性影院-国产精品线路一线路二-国产精品兄妹在线观看麻豆

The CD3 protein is a T-cell marker, a complex of four structurally distinct membrane glycoprotein isoforms, 20-50 kDa, comprising extracellular, transmembrane and intracellular domains. CD3 is associated with an heterodimer creating the T-cell receptor （TCR）. The CD3 complex is responsible for mediating signal transduction to the internal environment upon antigenic recognition by TCR, causing T-cell proliferation and release of cytokines.