CD2/LFA-3 ligation induces phospholipase-Cγ1 tyrosine phosphorylation and regulates CD3 signaling.

摘要: Activation of T cells through the TCR/CD3 receptor complex with either specific Ag or antibody results in tyrosine phosphorylation intracellular protein substrates and phosphatidylinositol-phospholipase C (PLC) signaling, leading to generation PI breakdown products mobilization calcium. Stimulation cell surface CD2 similarly propagates early signals phosphatidylinositol-PLC activation. Previous reports have shown that CD3 activation leads PLC isozyme gamma 1. In this report, we investigated potential similarity between CD3-induced signaling 1 induced by CD2. We show stimulation receptors on caused Cross-linking augmented tyrosine, whereas ligation CD45 phosphatase prevented phosphorylation. stimulated its counter-receptor form a soluble LFA-3/Ig fusion cross-linked surface, resulted low, but detectable level prolonged kinetics, cross-linking anti-CD2 was stronger transient. Co-ligation suboptimal concentrations anti-CD3 profound augmentation phosphorylation, calcium proliferation. To explore relationship CD3- CD2-stimulated were desensitized h incubation anti-CD3. modulation potently down-regulated CD2-induced mobilization. contrast, PMA ionomycin treatment did not alter 1, suggesting kinase inhibition events downstream Taken together, these support hypothesis provides potent co-stimulatory signal for is associated kinase(s)