N. 3 CD3 and CD4-mediated signalling and proliferation in resting and activated human T cells

摘要: We wanted to investigate the response of preactivated human T cells to stimuli given via TCR/CD3 and CD4. Six CD4+ T cell clones and resting T cells (RT) were stimulated by soluble anti-CD3 and/or anti-CD4. In some cases the mAbs were crosslinked on the cell surface using F (ab') 2 fragments of goat anti-mouse Ig in solution. Proteintyrosine phosphorylation (Tyr-P) and Ca2+ i were determined and compared with the proliferative response. The general level of Tyr-P correlated with increases of Ca2+ i but not with DNA synthesis. However, the phosphorylation of two substrates (100 KDa and 36 KDa) paralleled the increases of DNA synthesis in clones. In both RT and T cell clones Tyr-P and Ca2+ i increases were strikingly similar, whereas the proliferative responses differed. In RT anti-CD3 crosslinking abolished [1] and cocrosslinking with CD4 enhanced the anti-CD3 induced proliferation. This was not …