Cytokine profile of human PBMC following a 48 h in vitro stimulation with LPS, TSST-1, GP, GP + LPS and GP + TSST-1
Because of the GP-induced band shifts to seven sites from the TNFalpha, IL-8, IL-6 and IFNgamma promoters, it could be assumed that GP treatment of human PBMC would lead to production of TNFalpha, IL-8, IL-6, IFNgamma and other pro-inflammatory mediators. Previous studies reported that beta-1-->3-D-glucans induced only a limited cytokine secretion of human blood cells [15-18]. Corroborating and extending these singular findings in terms of examining pro- (eight) as well as anti- (three) inflammatory cytokines over time (48 h) and six additional transcription factor binding sites, our comprehensive analysis revealed the following cytokine profile of human leukocytes in response to a highly purified water soluble beta-1-->3-D-glucan and in comparison to two pro-inflammatory mediators (LPS, TSST-1): 
(i) IL-1beta
There was no IL-1beta production detectable following PBMC treatment with 1 nor 100 mug GP. An insignificant up-regulation of IL-1beta production for GP + LPS was observed in comparison with LPS. For GP + TSST-1 we found a significant reduction in IL-1beta 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-1beta by about 50% (Fig. 3A). 
(ii) IL-6
GP induced only a small amount of IL-6 and there was no significant alteration of the LPS-induced IL-6 production by GP. On the contrary, we observed a decreased IL-6 production for GP + TSST-1 when compared to TSST-1 or GP/TSST-1 calc., especially at 24 h by about 40% (n = 5; both p = 0.02), (data not shown in detail). 
(iii) IL-8
We found that GP induced a substantial IL-8 production, in comparison with medium control, especially at 24 h (n = 13; p < 0.01). A combination of GP and LPS resulted in a non-significant increase of IL-8 production when compared to LPS or GP/LPS calc. There was no significant alteration in IL-8 production following GP + TSST-1 when compared to TSST-1 or GP/TSST-1 calc. (data not shown in detail). 
(iv) IL-1RA
Besides IL-8, IL-1RA was the only mediator which was produced in significant quantities following GP treatment, especially at 24 h (n = 14, p < 0.01). When compared to LPS stimulation or GP/LPS calc., GP + LPS did not alter the kinetic course of the IL-1RA production. However, following GP + TSST-1 we found a synergistic increase in IL-1RA production from 18 h to 48 h, when compared to TSST-1 (for instance at 24 h: n = 6; p = 0.01) or to the theoretical value of GP/TSST-1 calc. (from 18 h to 36 h). Over the time course of 48 h, GP elevated the TSST-1-induced amount of IL-1RA by approximately 200% (Fig. 3B). 
Positive correlation between GP-induced IL-8 and IL-1RA productions. Following stimulation with GP (24 h), we observed a positive correlation between IL-8 and IL-1RA. Moreover, we found this correlation to be dose-dependent, since 100 mug of GP induced larger amounts of IL-8 and IL-1RA than 1 mug GP (n = 5, p </= 0.002, r = 0.9 and 0.98, respectively). 
(v) TNFalpha
With respect to TNFalpha production, 100 mug of GP yielded minor, statistically not distinguishable amounts, when compared to medium control. GP + LPS did not change the TNFalpha production when compared to LPS supplementation or GP/LPS calc. When combined with TSST-1 or GP/TSST-1 calc., GP seemed to exert a synergistic effect on TNFalpha secretion after 36 h (n = 3; p < 0.05), but overall an enhancement of only 10% was observed (p > 0.05; data not shown in detail). 
(vi) IFNgamma
No IFNgamma production was detectable following treatment of PBMC with 100 mug GP. There was a minor increase in IFNgamma production following GP + LPS at 36 h, when compared to LPS or GP/LPS calc., and a slight down-regulation following GP + TSST-1 at 24 h and 36 h, when compared to TSST-1 or GP/TSST-1 calc. (data not shown). 
(vii) IL-2, IL-12, IL-4, IL-10, TGFbeta1
The production of IL-2, IL-12, IL-4, IL-10 and TGFbeta 1 was not induced by GP. There were also no significant differences between medium control, LPS, TSST-1, GP, GP + LPS, GP/LPS calc. and GP + TSST-1 or GP/TSST-1 calc. over 48 h (data not shown). 
