Gene expression profiling of macrophages from conventional or antibiotic-treated mice

Antibiotic-treated (ABX) mice exhibit an impaired innate and adaptive antiviral immune response and substantially delayed viral clearance following exposure to systemic LCMV or mucosal influenza virus. Genome-wide transcriptional profiling of macrophages isolated from ABX mice revealed decreased expression of genes associated with antiviral immunity. Moreover, macrophages from ABX mice exhibited defective responses to type I and type II IFNs and impaired capacity to limit viral replication. Collectively, these data indicate that commensal-derived signals provide tonic immune stimulation that establishes the activation threshold of the innate immune system required for optimal antiviral immunity. In this study, we performed gene expression profiling to compare the transcriptional signatures of macrophages isolated from mice exposed to commensal bacteria-derived signals to macrophages isolated from mice depleted of commensal bacteria. Peritoneal macrophages (CD3ε-, CD5-, CD19-, CD11b+, F4/80+) from naïve CNV or ABX mice were sorted directly into TRIzol (Invitrogen) on a BD Aria (Beckson Dickson). Test sorts were ≥95% pure. For microarray analysis, RNA was extracted from 3 sorted biological replicates of peritoneal macrophages from naïve CNV or ABX mice. cDNA was amplified using NuGen WT Ovation Pico kit and hybridized to Affymetrix GeneChip Mouse Gene 1.0 ST microarrays