Evaluation of the specificity of the c-Rel antisera used by transfection and competition experiments.

(A-B) Transfection experiments. HEC 293 cells were transiently transfected with the Rc/CMV2 plasmid containing full-lengthREL cDNA (Aii and Bii) or with the Rc/CMV2 vector alone (Ai and Bi). In immunocytology with antisera 265 (A) and 1136 (B) on the paraffin sections of the pelleted cells, immunoreactivity is restricted to cells transfected with the vector containing full-lengthREL cDNA. Note that staining in some cells is exclusively localized in the nucleus (see inserts Aii,Bii); bar equals 37.5 μm; inset magnification, bar equals 18 μm. (C) Competitive experiments. cHL14 revealed a strong cytoplasmic and nuclear staining for c-Rel with c-Rel antisera 265 (Ci). Specificity of the staining was confirmed by complete absence of staining after simultaneous incubation with a specific peptide (Cii); bar = 25 μm. Stains described in “Materials and methods.”