Defective expression and enzymatic activation of cdk4 and cdk2 in IL-10 + TGF-β–tolerant cells.

(A) Lysates from unstimulated, tolerant, and primed T cells were analyzed by SDS-PAGE and immunoblotted with antiserum specific for cdk4, cdk6, or cdk2. (B) Immunoprecipitations were performed with anti-cdk4 or anti-cdk2 specific antiserum agarose conjugate and in vitro kinase reactions were done using Rb-GST or histone H1 as exogenous substrate, respectively. Reactions were analyzed by 10% SDS-PAGE, transferred to PVDF membrane, and exposed to x-ray film. (C) Lysates from unstimulated, tolerant, and primed T cells were analyzed by 6% SDS-PAGE, transferred onto nitrocellulose membrane, and immunoblotted with mAb specific for Rb.