[1 alpha, 25-dihydroxyvitamin D3 and its analogues modulate the phagocytosis of human monocyte-derived dendritic cells].
OBJECTIVE
To investigate the role of 1 alpha, 25-dihydroxyvitamin D3 (calcitriol) and its analogues tacalcitol and 24, 25(OH)2D3 on the phagocytosis of human monocyte-derived dendritic cells (MoDC).


METHODS
MoDC were generated in vitro by differentiating monocytes in the presence of GM-CSF and IL-4 for 5 days. Expression of mannose receptor (MR) and Fc gamma receptors (Fc gamma Rs) by MoDC was analysed by flow cytometry. Zymosan ingestion was measured to assess the phagocytosis of MoDC.


RESULTS
MoDC expressed high level of MR and Fc gamma Rs and showed the capacity of zymosan ingestion. Calcitriol and tacalcitol but no 24, 25(OH)2D3 not only upregulated the expression of MR and Fc gamma Rs on MoDC but also correspondingly enhanced their phagocytosis by increasing zymoasan ingestion. Furthermore, the upregulatory role occurred in the early stage of MoDC differentiation and was irreversible. The upregulatory role of calcitriol was dose dependent.


CONCLUSIONS
Calcitriol and its analogue tacalcitol may play an important role in dendritic cell binding and capturing foreign antigens at the initiation of immune response.
Zhu
Ke-jian
KJ
Department of Dermatology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, China. zhukejian@mail.hz.zj.cn
Zhou
Wei-fang
WF
Zheng
Min
M
D002117:Calcitriol / Q000494:pharmacology*; D002120:Calcium Channel Agonists / Q000494:pharmacology; D003713:Dendritic Cells / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D004100:Dihydroxycholecalciferols / Q000494:pharmacology*; D006801:Humans; D037181:Lectins, C-Type / Q000378:metabolism; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins / Q000378:metabolism; D009000:Monocytes / Q000166:cytology; D010587:Phagocytosis / Q000187:drug effects*; D011956:Receptors, Cell Surface / Q000378:metabolism; D017452:Receptors, IgG / Q000378:metabolism
D002120:Calcium Channel Agonists; D004100:Dihydroxycholecalciferols; D037181:Lectins, C-Type; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D011956:Receptors, Cell Surface; D017452:Receptors, IgG; C023850:1 alpha,24-dihydroxyvitamin D3; D002117:Calcitriol