FIG. 5.

TNF-inducing activities of lipid A and LPS from Y. pestis strain Yreka in RAW 264.7 murine macrophages. (A) RAW 264.7 cells were cultured in the presence of the indicated concentrations of synthetic lipid A 506 (▴), Y. pestis lipid A grown at 27°C (□), or Y. pestis lipid A grown at 37°C (•). (B) RAW 264.7 cells were cultured in the presence of the indicated concentrations of Salmonella serovar Abortus-equi LPS (▴), LPS of Y. pestis grown at 27°C (□), and LPS of Y. pestis grown at 37°C (•). Culture supernatants obtained at 24 h were assayed for determination of TNF-α activity. Data are means ± standard errors of the means from triplicate samples. Results of one experiment representative of three independent experiments are shown.