(i) IL-1β
There was no IL-1β production detectable following PBMC treatment with 1 nor 100 μg GP. An insignificant up-regulation of IL-1β production for GP + LPS was observed in comparison with LPS. For GP + TSST-1 we found a significant reduction in IL-1β from 18 h – 24 h, for the latter by about 40% when compared to TSST-1 or the theoretical value of GP/TSST-1 calc. (n = 6; both p = 0.01). On the whole, GP mediated a reduction of the TSST-1-induced amount of IL-1β by about 50% (Fig. 3A).
Figure 3  A, IL-1β was down-regulated (12 h – 24 h) following GP + TSST-1 when compared to TSST-1. Time course (48 h) of IL-1β production (pg/ml) by human PBMC incubated with medium control, 100 μg GP, 250 ng TSST-1, GP + TSST-1, 250 ng LPS and GP + LPS. At 18 h and 24 h there was a marked reduction in IL-1β production following GP + TSST-1 when compared to TSST-1 (* = p < 0.05). Graphs depicting the theoretical values for GP/LPS calc. and GP/TSST-1 calc. are also shown. IL-1β levels in the supernatnant were obtained by Elisa and are shown as mean ± SEM (n = 3). B, IL-1RA was exaggerated following GP + TSST-1 (12 h – 48 h) when compared to TSST-1. Time course (48 h) of IL-1RA production (pg/ml) by human PBMC incubated with medium control, 100 μg GP, 250 ng TSST-1, GP + TSST-1, 250 ng LPS and GP + LPS. Between 18 h and 48 h a simultaneous treatment of PBMC with GP + TSST-1 led to a synergistic effect, i.e. a higher IL-1RA production when compared to an addition of the single values for TSST-1 and GP (* = p < 0.05). Graphs depicting the theoretical values for GP/LPS calc. and GP/TSST-1 calc. are included. IL-1RA levels in the supernatnant were obtained by Elisa and are shown as mean ± SEM (n = 3).