Development of peritoneal macrophage along a dendritic cell lineage in response to uptake of oligomannose-coated liposomes

► We investigate the potential of peritoneal cells to differentiate into DCs. ► CD11c + cells arose among the OML-ingesting monocytes/macrophages during cultivation. ► CD11c + cells developed among enriched CD11b highCD11 − cells from OML-treated mice. ► The CD11c + cells derived from the CD11 − cells expressed co-stimulatory molecules. ► A fraction of peritoneal cells can differentiate into mature DCs by uptake of OMLs. In this study, we investigate the potential of peritoneal macrophages to differentiate into dendritic cell (DCs) in response to preferential uptake of oligomannose-coated liposomes (OMLs). About 30% of peritoneal cells (PECs) preferentially took up OMLs that were administered into the peritoneal cavity. The OML-ingesting cells expressed CD11b and F4/80, but lacked CD11c expression, indicating that the OML-ingesting PECs with a CD11b highCD11c − phenotype are resident peritoneal macrophages. During in vitro cultivation, CD11c + cells arose among the PECs with ingested OMLs. CD11c + cells also developed among enriched peritoneal CD11b highCD11 − cells from OML-treated mice, and the resulting CD11c + cells expressed co-stimulatory molecules and MHC class II. In addition, OML-ingesting CD11b highCD11c + cells were found in spleen after the enriched peritoneal macrophages with ingested OMLs were transplanted in the peritoneal cavity of mice. These results show that a fraction of peritoneal macrophages can differentiate into mature DCs following uptake of OMLs.