IFNB1 and infection: To directly clarify whether B. coccoides can promote systemic type I IFN responses through monocyte/macrophage activation, we infected bone marrow-derived macrophages (BMDMs) isolated from PBS-treated, Abx-treated, B. coccoides-colonized, or C. butyricum-colonized mice with EMCV at a multiplicity of infection (MOI) of 5 in vitro and detected induction of Ifnb and associated ISGs at 8 hpi using quantitative RT-PCR (qRT-PCR).