Effect of IVIg on cell cycle protein expression and apoptosis. Tonsillar B cells were incubated with anti-IgM–coated beads in the presence or absence of IVIg for 24 hours before lysis. Total cell lysates were separated and stained in WB with (A) anti-p27, anti-CDK2 and anti-E2F Abs, and (B) anti–caspase 9, anti–caspase 3, and anti-PARP Abs. Values indicate relative density of the bands normalized to that obtained for β-actin. Data are representative of 3 independent experiments.