Potentially even more relevant than the specific cytokine panel induced by GP, we found that, in the presence of other stimuli (LPS or TSST-1), GP ameliorated their pro-inflammatory immune reactions, similar to the effects in murine models of sepsis and inflammation [21-24]. Mainly, GP altered the TSST-1-induced IL-1β/IL-1RA ratio from a pro- to an anti-inflammatory profile via down-regulation of IL-1β and IL-6, at the same time there was a synergistic up-regulation of IL-1RA. In part, this change may be caused by GP-mediated modulations of the TSST-1 induced binding of NFκB, NFIL-6 and NFAT to known and up to now unknown sites within the IL-8 and IL-1RA promoter instead of the TNFα, IL-1β, IL-6 or IFNγ promoter. Accordingly, we found that the TSST-1-induced binding of NFκB to sites from the TNFα promoter negatively correlated with the GP-mediated enhancement of the TSST-1-induced IL-1RA production (r = -0.88; p < 0.01; data not shown in detail). Of the four examined NFκB sites from the IL-1RA promoter, mostly the TSST-1- and LPS-induced binding to the NFκB3 and the TSST-1-induced binding to the new NFκB consensus site seemed to be increased by GP. So, while we observed a GP-mediated down-regulation of the LPS- and the TSST-1-induced NFκB binding to sites of the TNFα promoter, there was an up-regulation to NFκB3 and NFκB consensus sites of the IL-1RA promoter. These seemingly contradictory data could be explained by differences in either NFκB subunits or conserved nucleotides (#1, 2, 3, 10) within the decameric NFκB binding motif between the TNFα and the IL-1RA promoter (for NFκB3 the IL-1RA motif contains a T on position 10 instead of the conserved C in the TNFα motif, see Table 1), probably leading to differences in binding [41,42]. Despite the location of the new NFκB consensus site (-266 and -280) in the inhibitory element (-250 and -294) of the IL-1RA promoter [30], we observed no inhibition. On the other side, we found an inhibitory NFκB2/3 site (-288 and -302) towards the end of the inhibitory element, demonstrating down-regulations of the LPS- and TSST-1-induced binding, which could not be altered by GP. In our opinion, this site may therefore represent at least a part of the previoulsy described inhibitory element [30]. The GP-modulated increase in TSST-1-induced binding to the new NFκB3 and NFκB consensus site, the NFIL-6 site [32] as well as to the novel NFATP2/3 site may explain the synergistic up-regulation of the TSST-1-induced IL-1RA production. We think that this GP-modulated activation of transcription was reflected by the decrease of the IL-1β/IL-1RA ratio following GP + TSST-1 (Fig. 6). In this context, it has been postulated that in vitro a 100fold excess of IL-1RA over IL-1β might control the biological effects of IL-1 [46,47]. Since, in fact, the IL-1β/IL-1RA ratio following GP + TSST-1 is partially less than 0.01, it is not unreasonable to assume that IL-1β bioactivity is inactivated in our system. Indeed, GP reduced the TSST-1-induced, IL-1-dependent IL-2 production of murine EL-4 cells (data not shown in detail).