Fig. 6. CD40 induces nuclear accumulation of p52–RelA and p52– RelB dimers in splenic B cells. (A) Lysates of unstimulated splenic B cells were immunoprecipitated with the indicated antibodies and western blotted. In the right hand panels, specific peptide was used to elute bound antigen to decrease background Ig. (B) Nuclear extracts were prepared from splenic B cells stimulated with CD40L for 0.5 or 5 h or left unstimulated. MG132 was added 15 min prior to stimulation. p52 was then immunoprecipitated and associated Rel subunits identified by western blotting. C indicates control IgG immunoprecipitations.