1 alpha, 25-dihydroxyvitamin D3 and its analogues modulate the phagocytosis of human monocyte-derived dendritic cells / 药学学报

ABSTRACT

<p><b>AIM</b>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).</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>Calcitriol and its analogue tacalcitol may play an important role in dendritic cell binding and capturing foreign antigens at the initiation of immune response.</p>