Baseline CD11b+ CD115+ Co-housed vs specific pathogen free monocytes
The immune system of SPF mice is dominated by naïve phenotype immune cells, especially within the T cell compartment, and resembles that of neonatal humans (Beura et al., 2016; Reese et al., 2016). Sequential infection of SPF-housed laboratory mice with common experimental pathogens, such as MHV, MCMV, Listeria monocytogenes, LCMV, and influenza A virus (Berton et al., 2022; Reese et al., 2016), or cohousing (CoH) SPF mice with pet store mice carrying multiple pathogenic and commensal bacteria, viruses, and/or fungi (Beura et al., 2016) induces immune system alterations and maturations that more closely resemble the adult human immune system. Such microbial exposure drastically alters the composition and function of the immune system of laboratory mice, which can significantly influence the overall outcome (and survival) to subsequent infection. Here we report CD11b+ CD115+ monocytes sorted from female specific pathogen-free (SPF) C57BL/6N (B6) mice co-housed with petstore mice for 60 days are transcriptionally different than SPF CD11b+ CD115+ monocytes Overall design: We performed gene expression profiling analysis using data obtained from RNAseq of sorted CD11b+ CD115+ monocytes from the spleens of four 60 day co-housed (with petstore mice)mice  and three specific pathogen free (SPF) mice