Effect of Mycobacterium phlei F.U.36 suspended liquor on culture and proliferation of dendritic cells derived from human umbilical cord blood in vitro

To investigate the effect of mycobacterium phlei F.U.36 suspended liquor (Utilin"s",U) on the culture and proliferation of dendritic cells (DCs) derived from human umbilical cord blood in vitro, the mononuclear cells (MNCs) were isolated from human umbilical cord blood and cultured with RPMI 1640 in the control group. Test groups consisted of Utilin"s" group (only Utilin"s"), GTI group (GM-CSF, TNF-α,IL-4) and GTIU group (GM-CSF, TNF-α,IL-4 and Utilin"s"). MNCs in all test groups were cultured with RPMI-1640. The growth of DCs was observed by the light microscopy, the phenotypes of DCs were determined by flow cytometry on the 10th day of culture, and some harvest cells were stained with Wright-Giemsa, then observed and photographed under the oil immersion objective. The results showed that the test groups all displayed some number of typical DCs; both CD1a positive cell rate and HLA-DR positive cell rate of the Utilin"s" group were higher than those of the control; HLA-DR positive cell rate of GTIU group increased most significantly and much higher than that of the GTI group. It is concluded that mycobacterium phlei F.U.36 not only promotes the proliferation of DCs derived from human umbilical cord blood in vitro, but also co-operates with rhGM-CSF, rhTNF-α and rhIL-4 in promoting the maturity of DCs.