Distinct murine mucosal Langerhans cell subsets develop from pre-DCs and monocytes. Mus musculus

Langerhans cells (LCs) populate the mucosal epithelium, a major entry portal for pathogens, yet their ontogeny remains unclear. In contrast to skin LCs originating from self-renewing radioresistant embryonic precursors, we found that oral mucosal LCs derive from circulating radiosensitive precursors. Mucosal LCs can be segregated into CD103+CD11blow (CD103+LCs) and CD11b+CD103- (CD11b+LCs) subsets. We further demonstrated that similar to non-lymphoid dendritic cells (DCs), CD103+LCs originate from pre-DCs, whereas CD11b+LCs differentiate from both pre-DCs and monocytic precursors. Despite this ontogenetic discrepancy between skin and mucosal LCs, transcriptomic signature and immunological function of oral LCs highly resemble those of skin LCs but not DCs. These findings, along with their epithelial position, morphology and expression of LC-associated phenotype strongly suggest that oral mucosal LCs are genuine LCs. Collectively, in a tissue-dependent manner, murine LCs differentiate from at least three distinct precursors (embryonic, pre-DCs and monocytic) in steady state Overall design: The following cells were isolated from mice (2-4 replicates): Lung DCs, mucosal CD103+ LC, mucosal CD11b+ LC, Skin LC. Transcriptome analysis was performed.