Binding activities of NFkappaB, NFIL-6 and NFAT from human PBMC to the TNFalpha, IL-6 and IFNgamma promoters following an in vitro stimulation (1 h) with LPS, TSST-1, GP, GP + LPS and GP + TSST-1
GP induced band shifts, indicating binding of NFkappaB as well as of NFIL-6 to the corresponding DNA oligonucleotides (kappa consensus, kappa1, kappa2, kappa3 sites from the TNFalpha promoter; kappa consensus from the IL-8 promoter; NFIL-6consensus from the IL-6 promoter; Table 1; Fig. 1A). The extent of the band shifts induced by GP was not statistically different when compared to LPS or TSST-1 (Fig. 1B). A supershift, conducted for an NFkappaB consensus site from the IL-8 promoter, demonstrated a GP-induced predominant binding of NFkappaB p65 and to a lesser degree of p50 (Fig. 1A). Accordingly, an immunoblot of nuclear extracts from GP-treated PBMC showed a strong binding of NFkappaB p65 and a weaker reaction of p50, whereas p52 was negative (Fig. 2). Simultaneous co-treatment of PBMC with GP did not change the LPS-induced NFkappaB binding to oligos from the TNFalpha promoter significantly (Fig. 1B), but substantially decreased the TSST-1-induced NFkappaB binding when compared to TSST-1 or GP (100 mug) and thus differed completely from the theoretical value of GP/TSST-1 calc. (n = 4; p < 0.05 vs. GP/TSST-1 calc. and p = 0.07 vs. TSST-1; Fig. 1B). GP was also able to induce band shifts indicative of binding of particular variants of NFAT to an oligo from the IFNgamma promoter (Fig. 1A). An immunoblot for two NFAT subunits demonstrated a GP-induced binding of NFATc2 and to a lesser degree of NFATc1 (Fig. 2). 
