Expansion and function of MHC restricted killer T cells derived from umbilical cord blood / 中国实验血液学杂志

ABSTRACT

<p><b>OBJECTIVE</b>This study was to expand the cytotoxic T lymphocytes (CTL) through inducing the differentiation of umbilical blood monomuclear cells (UBMNC) by using various combination of cytokines, and to investigate the functions of expanded CTL.</p><p><b>METHODS</b>The MNC were isolated by ficoll density gradient centrifugation. Then, the PHA-P, IFN-γ combined with IL-2, IL-15 and other cytokines were used for induction and expansion of the cord blood-derived CTL. The biological function of CTL was examined by phenotype analysis, cytotoxic tests and real-time fluorescence quantitative PCR.</p><p><b>RESULTS</b>After expansion for 15 days, the cell number increased by 1522% ± 137%. The content of CD3(-)CD8(-) cells in uncultured cord blood MNC was 95%, and the CD3(+)CD8(+) CTL cells reached 82.77% in cultured cord blood MNC after expansion for 15 days. The expanded CTL cell showed the cytotoxic activity against K562 and HeLa cell line. The killing rate of MNC was 61.88 ± 1.08%. After expansion, the killing rate could reach to 90% with the average value of 90.33 ± 2.02%. The expanded CTL cells highly expressed some key cytokines, such as granzyme A, granzyme B, GM-CSF, granulysin, IFN-γ, TGF-β, TNF-α and perforin. Compared with the control group, the expression of IFN-γ and TGF-β significantly increased (P < 0.05), and the other factors dramatically increased (P < 0.01).</p><p><b>CONCLUSION</b>The cord blood-derived CTL can be expanded by different combinations of cytokines. These protocols may provide alternative choices for CTL cell expansion in tumor adoptive immunotherapy.</p>