Induction of LMP-1 by hIL-10 in NK-cell lymphoma lines. (A) Expression of IL-10R assessed by SDS-PAGE and immunoblotting in total cell lysates of SNK-6 and KAI-3 cells cultured in the presence or absence of hIL-2. The membrane was stripped and reprobed with anti-β-actin antibody to serve as loading control. (B) Immunoblot analysis of total cell extracts of IL-2- or IL-10-treated SNK-6 with phospho-STAT3 (Tyr705)- and total STAT3-specific antibodies. (C) LMP-1 and β-actin expression in IL-2- or IL-10-treated (48 hours) SNK-6 and KAI-3 cells assessed by SDS-PAGE and immunoblotting. Of note: all immunoblots of NK lymphoma line extracts were probed with the less sensitive anti-LMP-1 monoclonal Ab mixture CS1-4 (in comparison with the anti-LMP-1 S12 monoclonal Ab used in all the previous figures). (D) LMP-1 and β-actin immunoblot of SNK-6 cells treated with 1, 10, 50, or 100 ng/mL hIL-10 for 48 hours.