[Induction of monocyte-derived dendritic cell differentiation by asthmatic serum in a transendothelial trafficking model].

Objective: To explore the effect of asthmatic and healthy serum on differentiation and function of monocyte-derived dendritic cells (MDDC) in a transendothelial trafficking model.

Methods: The sera and peripheral blood mononuclear cells (PBMC) were separated from 12 asthmatic patients and 12 healthy volunteers, and monocytes were selected from PBMC using magnetic beads. The trypsin-digested human umbilical vein endothelial cells (HUVEC) at passage 2 from 5 healthy lying-in women were used to construct the transendothelial trafficking model under asthmatic or healthy serum, wherein MDDC were identified by silver nitrate staining and scanning electron microscopy. Nuclear factor κB (NF-κB) activity was determined by electrophoretic mobility shift assay. Flow cytometry, ELISA and mixed leukocyte reaction were relevantly utilized to detect the phenotype, cytokine and T cell proliferation.

Results: (1) Monocytes traversed through HUVEC monolayer after 2 h, and reverse-transmigrated to develop into DC 48 h later. (2) The healthy serum stimulated monocytes into immature MDDC with lower CD(14) [(20 ± 5)%] (F = 49.01, P < 0.05), and higher HLA-DR, CD(80), CD(86) and CD(83) [(43 ± 4)%, (17.9 ± 3.5)%, (43 ± 11)% and (6.7 ± 1.8)%, respectively] (F = 10.35 - 40.17, all P < 0.05) than monocytes did before transmigration at 0 h [CD(14) (81 ± 6)%, HLA-DR (24 ± 5)%, CD(80) (2.8 ± 2.0)%, CD(86) (14 ± 4)% and CD(83) (0.9 ± 0.8)%, respectively]. (3) The asthmatic serum stimulated monocytes into mature MDDC, characteristic of dendrites, with similar HLA-DR and CD(86) [(55 ± 6)% and (59 ± 12)%] (F = 15.29 and 35.97, all P > 0.05), higher CD(80) and CD(83) [(49.7 ± 10.2)% and (30.2 ± 6.8)%] (F = 4.01 and 20.68, all P < 0.05), accompanied by increased levels of NF-κB activity, IL-12 p70 and T cell proliferation [(100 ± 11)%, (568 ± 43) ng/L and (2033 ± 198) cpm, respectively] (F = 49.23 - 350.84, all P < 0.05) relative to the healthy serum-stimulated immature MDDC [(12 ± 3)%, (220 ± 35) ng/L and (952 ± 64) cpm, respectively].

Conclusion: The asthmatic serum induces mature MDDC in association with NF-κB overactivation in the transendothelial trafficking model, which provides a promising experimental platform for both investigation of immunological mechanisms in asthma and screening of novel anti-asthma drugs in vitro.