NF-κB2 protein expression in PBMCs. (A-C) Immunoblot of wild-type and mutant NF-κB2 in PBMCs from healthy normal control and patients. Total PBMCs were treated with α-CD3 to stimulated NF-κB2 pathway for 48 hours. Cell lysates were prepared and analyzed for phosphorylation of p100 and for full-length (p100) and active form (p52), and mutant expression by western blotting. Immunoblotting of β-actin was used as a loading control. Red asterisks indicate mutant form of NF-κB2 in patient cells. Due to the similar size between mutant E418X and active form of NF-κB2 (p52), it was difficult to discriminated mutant (E418X) from active form of NF-κB2 in stimulated condition in patient A1.