text: Role of NFkappaB, NFIL-6 and NFAT binding in LPS-, TSST-1-, GP-, GP + LPS- and GP + TSST-1-induced IL-1RA expression by human PBMC
  Because GP induced band shifts to NFkappaB, NFIL-6 and NFAT sites, but no TNFalpha, IL-6 or IFNgamma, we hypothesized that the activated transcription factors might bind to sites in the IL-1RA promoter. We investigated previoulsy described and newly discovered transcription factor binding sites of the IL-1RA promoter (Table 1) using the program OMIGA (v.1.1.3, Oxford Molecular, Oxford, UK). The LPS responsive kappaB consensus site of LRE-1 (between -84 and -93) [30] displayed band shifts, but no significant alterations of its binding activity, irrespective of the treatment (data not shown). A new kappaB3 site (-100 and -130) within the LRE-1 [30] showed increased binding induced by TSST-1 (+30% vs. control), but GP co-treatment up-regulated the LPS (+65% vs. control)- and the TSST-1 (+110% vs. control)-induced binding in a superadditive synergistic fashion, when compared to medium control as well as to LPS, TSST-1 or GP or the theoretical values of GP/LPS calc. or GP/TSST-1 calc. (all p < 0.05; Fig. 4). Binding to a new kappaB consensus site (between -266 and -280) was significantly elevated for GP + TSST-1 (p < 0.05; data not shown). The LPS-, TSST-1- and GP + LPS-induced binding to the new kappaB2/3 site (-288 and -302) was down-regulated by about 20-35% in comparison with medium control (p < 0.05; data not shown). The NFIL-6 site (-147 and -170) close to LRE-2 [31,32] showed an up-regulation of binding for all compounds and combinations vs. medium control, ranging from 25-110% (p < 0.05). Further, GP + TSST-1 induced an increased binding to the NFIL-6 site in comparison with TSST-1 (1.3fold) or GP (1.6fold; p < 0.05), (data not shown). A new binding site for NFATP2/3 was found more distal of the transcription start site, between -471 and -490, displaying again a substantial increase of binding for all compounds and combinations, when compared to medium control (p < 0.05). In addition, binding to the NFATP2/3 site following both, GP + LPS (1.4fold of GP) and GP + TSST-1 (1.5fold of GP, 1.25fold of TSST-1) was elevated (p < 0.05; Fig. 5), but only in an additive synergistic manner, i.e. the experimental results were not different from the theoretical values (calc.). 
  