FIG 6.
Liver CD4+ T cells are unable to control intracellular bacterial replication in macrophages, and liver macrophages have an M2-like phenotype during chronic Salmonella infection. (A) Liver or spleen CD4+ T cells from chronically infected mice (139 days postinfection) were purified and cocultured with Salmonella-infected Raw 264.7 macrophages. Infection only refers to RAW264.7 macrophages that were infected with Salmonella in the absence of any T cells. Macrophage bacterial burdens were assessed at the indicated time points. One-way ANOVA with Tukey’s post hoc analysis was used to determine statistical significance between groups. *, P < 0.05; **, P < 0.01; ***, P < 0.001. (B) RNA was extracted from purified splenic or liver macrophages from mice 111 days postinfection. Real-time quantitative PCR (RT-qPCR) results were analyzed using the threshold cycle (ΔΔCT) method, normalizing samples to GAPDH and comparing relative expression levels to those in naive, uninfected splenic or liver macrophages. Two-way ANOVA with Sidak’s multiple-comparison test was used to determine statistical significance between groups. *, P < 0.05; ***, P < 0.001; ****, P < 0.0001. Representative of 4 independent experiments (A) and 3 independent experiments (B).