Diptheria toxin dependent depletion and engraftment kinetics of dendritic cell subsets in the lungs of chimeric zDC+/DTR mice

Introduction:

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 pulmonary DCsubsets.

Methods:

We here characterized the kinetics of diphtheria toxin (DT) -induced selective depletion of pulmonary DC and its repopulation within the lung by employing CD45.2pos zDC+/DTR mice expressing human diphtheria toxin receptor (DTR) under control of the DC-specific transcription factor zbtb46 (zDC), allowing specific depletion of DC while sparing macrophages. Bone marrow (BM) from CD45.2pos zDC+/DTR mice was transplanted onto irradiated CD45.1pos WT mice, followed by treatment of the resulting chimeras with diphtheria toxin (DT) for selective depletion of CD11bpos and CD103pos DC subsets for up to 14 days.

Results and Discussion:

Engraftment of CD45.2pos donor-type CD11bpos and CD103pos DC subsets and macrophages from zDC+/DTR mice in lung tissue of chimeric CD45.1pos 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 48h for up to 14 days. CD103pos DCs were found to be more sensitive to DT challenge compared to CD11bpos DCs. Depletion of DC subsets in a model of AdTGF-β1 induced pulmonary fibrosis resulted in > 70% depletion of CD11bpos DC and > 98% depletion of CD103pos DC, thus proving the current depletion strategy as valid experimental approach for future examination of DC pathogenesis in pulmonary fibrosis.

*Presenting author