Effects of immunoglobulin D on expression of IgD receptor and protein tyrosine kinase signaling in human CD4+ T cells / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To observe whether human CD4 + T cells could be activated by immuno-globulin D (IgD) via IgD receptor(IgDR)-Lck. METHODS Human CD4+ T cells were purified from peripheral blood mononuclear cells (PBMCs) with microbeads. The viability of T cells were detected by CCK-8. The binding affinity and expression of IgDR on T cells were detected by flow cytometry. The protein expression of IgDR, Lck and P-Lck were analyzed by western blot. RESULTS IgD could concentration-dependent bind to IgDR on CD4+ T cells. The expression of IgDR was increased in response to treatment with IgD in a time- dependent and concentration- dependent manner. Stimulating by IgD resulted in enhanced phosphorylation of Lck compared with that in the medium control sample. The expression of Lck was not changed. As inhibitor of PTK, Herbimycin A or A770041, which combined with IgD could significantly inhibit phosphorylation of Lck(Tyr394). The proliferation promoting effect of IgD was blocked by Herbimycin A or A770041. IgD could stimulate CD4+ T cell activation and proliferation through upreg?ulating activating tyrosine residue of Lck (Tyr394) phosphorylation. CONCLUSION These results demon?strate that IgD exaggerates CD4+T cell activities, which may be through promoting Lck phosphorylation.