Brucella Control of Dendritic Cell Maturation Is Dependent on the TIR-Containing Protein Btp1 (original) (raw)
Figure 6
Btp1 Reduces DC Maturation
(A) Identification of Btp1 as bacterial member of TLR/IL-1R (TIR) family. Comparison of the predicted amino acid sequences of Btp1 with the human members of the TIR family: TLR2, TLR4, Single Immunoglobulin IL1-R related molecule (SIGIRR), Myeloid Differentiation protein 88 (MyD88), and IL-1 Receptor accessory protein (IL-1R acP). Significant sequence similarity is observed in Box 1 and Box 2, which are important signatures of all TIR domain proteins. The alignment was constructed with T-Coffee::advanced server from EMBnet (http://www.ch.embnet.org/). The color scheme is represented in the figure and is indicative of the reliability of the alignment, with red corresponding to highest probability of correct alignment. DCs infected with wild-type B. abortus or _btp1_− were either (B) fixed at 24 h and immunolabelled for MHC II (red) and Brucella (green) or (C) cells were lysed at 2, 24, and 48 h and CFU enumerated.
(D) Quantification of the percentage of DCs containing DALIS. DCs were incubated for 24 h with media (negative), heat-killed B. abortus (HKB), wild-type B. abortus (wt), _btp1_− mutant strain or a _btp1_− mutant with a plasmid containing btp1 (btp1_−p_btp1). There is a very significant statistical difference between the wt and _btp1_− (p = 0.0002) but only a small difference between _btp1_− and btp1_−p_btp1 (p = 0.05).
(E and F) Analysis of TNF-α and IL-12 (p40/p70) secretion measured by ELISA from the supernatant of DCs 24 and 48 h after inoculation. All the results correspond to the means ± standard errors of four independent experiments. A statistical difference was observed between wild-type Brucella and btp1 mutant at 24 h for TNF (p = 0.029) and IL12 (p = 0.045).