Comparison of several LPSs carrying different structure moieties in GM-DCs revealed a shield function of the Brucella core component. GM-DCs were non-treated (Mock) or stimulated with Bm-wt LPS, Bm-wadC LPS, Ochrobactrum anthropi 331 LPS, Yersinia enterocolitica O:9 LPS or E. coli LPS for 24 h. Brucella LPSs, Y. enterocolitica and O. anthropi LPS were used at the concentration of 10 μg/mL and E. coli LPS was at 100 ng/mL. (A) MHCII and co-stimulatory molecule levels of expression (MFI, Mean of Fluorescence Intensity) were measured by flow cytometry. (B) Cytokine secretion was determined in culture supernatants by ELISA. The graphs show combined data from at least three independent experiments. All error bars are standard deviations obtained from pooled data. Significant differences from mock or from Bm-wt LPS are shown. *, P < 0.05; **, P < 0.001; ***, P < 0.0001; ****, P < 0.00001. ns, non-significant.