Figure 5. Exosomes isolated from M.tb-infected cells inhibit a subset of IFN-γ inducible genes which partially overlaps with those inhibited by an M.tb infection.

BMMØ were treated with exosomes isolated from RAW264.7 cells (uninfected/infected)or were infected with M.tb followed by incubation +/− IFN-γ. RNA was isolated, converted to double-stranded cDNA, labeled with Cy3 and hybridized to Musmusculus 4×72 whole genome array. Genes up-regulated or down-regulated by each treatment were identified on the basis of ≥2 fold change in gene expression and a p value ≤0.05 as defined through three independent microarray experiments. Results are represented as Venn diagrams showing the total number of genes identified as well as the number of genes which overlap between treatment groups (A and B). Genes induced by IFN-γ were further analyzed for suppression by exosome pre-treatment or H37Rv infection. Similar analysis was performed on genes suppressed by IFN-γ whose expression was “rescued” by exosome pre-treatment or H37Rv infection. Results are depicted as pie charts showing the number of IFN-γ-induced genes not inhibited by any treatment, those inhibited by treatment or infection and those common to both groups (C). Similarly, results are shown for genes rescued by exosomes or H37Rv infection (D).