[In vitro studies on dendritic cell derived from cord blood and its role in antitumor immunity]

To investigate the way of inducing dendritic cell (DC) from precursor in cord blood and its role in antitumor immunity.

Cord blood was collected under sterile condition and the mononuclear cells (MNCs) were separated by centrifugal in density gradient (Ficoll-Hypaque). The adhesion cells, collected among the MNCs, were cultured with interleukin-4 (IL-4, 50 ng), granulocyte-macrophage colony-stumilating factor (GM-CSF, 100 ng) and tumor necrosis factor alpha (TNF-alpha, 1-2 ng) in dulbecco's modified eagles medium (DMEM) medium. Cell phenotype was analyzed on 10th day with CD1a, CD16, CD14, CD19, CD40, CD56, CD80, CD83, and human leukocyte antigens-D-related (HLA-DR) antibody by using indirect immunofluorescence assays. After cultured with tumor cytolysis antigen for 2 days, the cells were incubated with auto T cell separated by E-rosette formation. Methyl thiazolyl tetrazolium (MTT) assay was employed to test inhibition rate of tumor specific cytotoxic T lymphocyte (CTL) on HO9810 tumor cell line.

Our results indicated that DC precursors in cord blood can be induced to differentiate and mature in the medium containing IL-4, GM-CSF, and TNF-alpha. Some DC specialized antigens expressions were seen on 10th day after cultured with cytokines. After incubation with tumor cytolysis antigen, the DC can activate the CTL to become tumor specialized CTL, which had shown significantly inhibition on growth of HO9810 tumor cell line.

Primary in vitro experiment has shown that the precursors in cord blood can be induced to functional DC which activate T lymphocyte to become tumor specialized CTL. Our result indicate that it is an efficient and convenient way in antitumor immunity by inducing DC precursors in cord blood to functional DC and may have a great implication on clinical application.