Characterization of diphtheria toxin-induced engraftment and depletion of dendritic cell subsets in the lungs of chimeric zDC+/DTRmice

Abstract

Dendritic cells (DC) are suggested to play a role in various diffuse parenchymal lung diseases, but their pathogenetic relevance is poorly defined, due to lack of appropriate techniques to specifically deplete DC from the lung compartment. We here characterized the kinetics of diphtheria toxin (DT) -induced selective DC depletion from the pulmonary compartment by employing CD45.2 pos zDC +/DTR mice expressing human diphtheria toxin receptor (DTR) under control of the DC-specific transcription factor zDC. Bone marrow from CD45.2 pos zDC +/DTR mice was transplanted onto irradiated CD45.1 pos WT mice, followed by treatment of the resulting chimeras with diphtheria toxin (DT) for selective depletion of CD11b pos and CD103 pos DC subsets for up to 14 days. Engraftment of CD45.2 pos donor-type macrophages and DCs from zDC +/DTR mice in lung tissue of chimeric CD45.1 pos recipient mice was achieved at 7 weeks after BM transplantation. A single DT injection in chimeric mice resulted in successful DT-induced depletion of DC subsets but not macrophages for 3 days, while sustained DC depletion required a repetitive DT application every 48 h for up to 14 days. CD103 pos DCs were found to be more sensitive to DT challenge compared to CD11b pos DCs. Depletion of DC subsets in a model of AdTGF-β1 induced pulmonary fibrosis resulted in > 70 % depletion of CD11b pos DC and > 98 % depletion of CD103 pos DC, thus proving the current depletion strategy as valid experimental approach for future examination of DC pathogenesis in pulmonary fibrosis.