Confirmation of LTβR stimulation: induction of RelA- and RelB-containing DNA-binding complexes. Wild-type, relA-/-, and relB-/- MEFs were treated with agonistic anti-LTβR mAb for the indicated times and subsequently nuclear extracts were prepared and analyzed by EMSA for NF-κB DNA-binding activity using an Igκ oligo. Specific Igκ DNA-binding complexes are indicated by arrow (RelA-containing dimers) and arrowhead (RelB-containing dimers). Non-specific DNA binding complexes (ns, lower lane) serve as loading control. Supershift analysis was performed using pre-immune serum (pre-imm. serum), anti-RelA antibody (α-RelA Ab), and anti-RelB antibody (α-RelB Ab). Supershifted complexes are indicated by asterisk.