Activation of NF-κB in murine CIA. Mice were immunized with type II collagen on days 0 and 20 and boosted with lipopolysaccharide on day 28. Electromobility shift assays were performed on nuclear extracts of ankle joints at various time points during the evolution of disease. The right side of the gel shows NF-κB binding to labeled consensus NF-κB oligonucleotide, while the left side shows lack of binding to a mutant NF-κB oligonucleotide. Note that NF-κB binding activity was observed as early as 10 days after immunization, even though clinical arthritis was not observed until approximately day 30. Con, positive control.