Expression and functionality of IL-10R in BL lines. (A) IL-10R alpha expression of BL lines assessed by SDS-PAGE and immunoblotting. Jurkat cells were used as negative control. TB indicates tonsillar B cells. The membrane was stripped and reprobed with anti-β-actin antibody to serve as loading control. On all immunoblots the arrowheads on the left side indicate the location of the specific band, whereas the numbers on the right side denote the apparent molecular weight (kDa) of the prestained protein ladder. (B) Immunoblot analysis of total cell extracts of IL-10-treated (100 ng/mL, 30 minutes) BL lines with phospho-STAT3 (Tyr705)- and total STAT3-specific antibodies. YT NK lymphoma cells were used as positive control.