文本框: EFFECTS OF BCG ON THE APOPTOSIS OF CORD BLOOD MONOCYTE-DERIVED DENDRITIC CELLS IS DIFFERENT IN CULTURE MEDIUM WITH OR WITHOUT SERUM Liu EM, Law HKW and Lau YL Dept. of Paediatrics, The University of Hong Kong, Hong Kong, China Objective: We have previously shown that BCG promotes cord blood monocyte-derived dendritic cells (DCs) maturation with up-regulation in nuclear Rel-B and degradation of cytosolic IkBa and b. In the present study, we investigated that the effects of BCG on the survival and apoptosis of cord blood monocyte-derived DCs in culture medium supplemented with or without serum. Methods: CD14 positive monocytes were purified from cord blood mononuclear cells by immunomagnetic separation and were cultured in IL-4 and GM-CSF for 5 days. BCG was then added for further two days. Cell apoptosis was evaluated by annexin V – popidium iodide staining as detected by flow cytometry. The tissue cultures were performed in RPMI-1640 + 10% FCS or serum free and hormone free medium (DMEM-F12) Results: In serum-supplemented culture medium, BCG significantly maintained cord blood monocyte-derived DCs survival and inhibited their apoptosis. On the contrary, in serum free culture, BCG significantly decreased the percentage of living DCs and increased significantly the percentage of late apoptotic DCs. Conclusions: These results suggest that in addition to the promotion of cord blood monocyte-derived DCs maturation, BCG could either maintain DCs survival or promote their apoptosis in different condition. The mechanisms involved and its clinical significance in terms of potentiating BCG efficacy should be further investigated. 1916