Ps. a. filtrate increased nuclear content of NF-κB and AP-1 transcription factors. Nuclear extracts were prepared from day-21 hTBE cell cultures challenged apically with Ps. a. filtrate or IL-1β at the times noted and equal amounts of nuclear protein per lane were subjected to EMSA using oligonucleotide probes for NF-κB (A) or AP-1 (B). The inhibitor and supershift assays were all performed with nuclei extracted 2 hours after TSB or Ps. a. challenge. The results are representative of 3 separate experiments with cells derived from 3 different donors.