Figure 1: The LPS structure and the effects of the R- and S-forms on IFNγ production by NK cells. (a) The scheme of the LPS structure. The frontier between inner and outer core is marked by a bold line. The scheme has been taken from Bagheri et al. [14]. (b) Analysis of LPS samples by SDS-PAGE followed by silver staining. All samples were applied on gel in a concentration of 1 μg/lane. (c) The effects of S- and R-LPS on IFNγ production by NK cells. IL-2 (500 U/ml) was added to the cell culture together with LPSs. Data for eight experiments performed on NK cells isolated from blood samples taken from different donors, in triplicate wells, are shown. Here and after data are and asterisks denote significant differences (; ) from control samples with IL-2 only.