Brucella Control of Dendritic Cell Maturation Is Dependent on the TIR-Containing Protein Btp1 (original) (raw)
Figure 5
B. abortus Interferes with DC Function
(A) and (B) B. abortus blocks secretion of pro-inflammatory cytokines.
(A) Supernatants were obtained at 24 h from DCs inoculated with either media (negative), B. abortus, S. typhimurium, or heat-killed B. abortus (HKB) and the levels of cytokines were determined by ELISA. Values correspond to means ± standard errors of at least three independent experiments. A clear statistical difference was observed between Brucella and Salmonella for TNF (p = 0.014) and IL12 (p = 0.0098) and to a lesser extent for IL6 (p = 0.041) and IFNß (p = 0.040).
(B) DCs were infected for 4 or 24 h with either media (negative), B. abortus or S. typhimurium constitutively expressing GFP. DCs were then treated for 1 h with brefeldin A, permeabilised and labelled with anti-CD11c and anti-IL12 (p40/p70) conjugated with APC and PE, respectively. Representative dot blots are shown for CD11c+ populations.
(C) B. abortus reduces the capability of DCs to induce T cell proliferation. DCs were infected with wild-type B. abortus and the model antigen ovabulmin (OVA) was added after 30 min at a final concentration of 50 μg/ml. Cells were stimulated with OVA for 2 h and then washed to remove the antigen. Splenic CD4+ T cells prepared from OTI and OTII transgenic mice were then added at a 1:1 ratio and co-cultured for 48 h. IL-2 production in culture supernatants was measured by 3H-thymidine incorporation on the IL-2-dependent CTLL-2 cell line. Data are the means ± standard errors from triplicates of a representative experiment. A small statistical difference was observed between Ova and Ova+Brucella for both OT1 (p = 0.035) and OT2 (p = 0.045).