Ledbetter J A, Gilliland L K, Schieven G L
Oncogen Corporation, Seattle, WA 98121.
Semin Immunol. 1990 Mar;2(2):99-106.
Phosphorylation of proteins on tyrosine residues during activation was studied in CD3+ CEM T cells. Crosslinking of either CD4 alone or CD3/Ti alone induced weak and transient responses, but the patterns of induced tyrosine-phosphorylated proteins were different. A synergistic but still transient response occurred by the specific interaction of CD4 with CD3/Ti, whereas simultaneous but separate ligation of CD3/Ti and CD4 decreased rather than increased tyrosine phosphorylation of proteins in comparison to CD3/Ti stimulation alone. Stimulation of T cells with immobilized anti-CD3 induced strong and prolonged tyrosine phosphorylation of distinct substrates. CD4 therefore regulates protein tyrosine kinase activation by specific interaction with CD3/Ti, whereas immobilized anti-CD3 may differ from anti-CD3 in solution in the activation of protein tyrosine phosphatase(s) such as CD45.
在CD3 + CEM T细胞中研究了激活过程中酪氨酸残基上蛋白质的磷酸化。单独交联CD4或单独交联CD3/Ti会诱导微弱且短暂的反应，但诱导的酪氨酸磷酸化蛋白的模式不同。CD4与CD3/Ti的特异性相互作用会产生协同但仍短暂的反应，而与单独的CD3/Ti刺激相比，同时但分别连接CD3/Ti和CD4会降低而非增加蛋白质的酪氨酸磷酸化。用固定化抗CD3刺激T细胞会诱导不同底物的强烈且持久的酪氨酸磷酸化。因此，CD4通过与CD3/Ti的特异性相互作用调节蛋白酪氨酸激酶的激活，而固定化抗CD3在激活蛋白酪氨酸磷酸酶（如CD45）方面可能与溶液中的抗CD3不同。
