OBJECTIVESTry to induce liver-derived dendritic cells proliferation by plasmid-IL-3 and CD40L genes in mice in vivo.

METHODSRapid tail-vein injection of large amounts of plasmid-carrying genes was performed to transfect genes in mice livers. Liver nonparenchymal cells were isolated by Percoll gradient centrifugation. Dendritic cell markers were detected and dendritic cells were sorted out by flow cytometry. Morphology of dendritic cells was studied microscopically (with Giemsa staining) and under scanning electron microscopy.

RESULTSLiver nonparenchymal cells dramatically increased in the liver lobules, portal and periportal areas in the treated group, but not in the control group. B220+/DEC205+ dendritic cells were detected and sorted by flow cytometry. There were more B220+/DEC205+ dendritic cells (16.0%) in the experiment group than those in the control group (1.1%). Morphologically, the sorted B220+/DEC205+ cells showed irregular shaped nuclei, paucity of cytoplasmic granules and extensive cytoplasmic processes.

CONCLUSIONB220+/DEC205+ dendritic cells were expanded in vivo in mice livers by rapid tail-vein injection of plasmid-carrying genes encoding IL-3 and CD40L in a large amount. Inducing liver dendritic cell proliferation in vivo provides a more convenient way for studying the biology of these cells.