Of note, the observed amplification of COX-2 induction was not dependent on the timing of infection and stimulation: a similar degree of COX-2 upregulation was observed in GFs infected with P. gingivalis for 2 h prior to washing and subsequent stimulation with TNF and in cells that were subjected to simultaneous infection and stimulation (Fig. S1B). The gene discussed is PTGS2; the disease is infection.