TGF-β does not inhibit Lck or ZAP-70 phosphorylations but inhibits ERK phosphorylation. Whole cell lysates were prepared from CD4 + T cells stimulated by cross-linking anti-CD3 and anti-CD28 bound to cells under neutral conditions (IL-2, 50 U/ml) in the presence or absence of TGF-β (50 pM). Total cell lysates were prepared and analyzed for the phosphorylation of (A) Lck and ZAP-70 or (B) ERK, JNK, and GSK-3.
{}