Objective: To investigate the molecular mechanism underlying T-bet mediated anti-neoplastic effects of
cytokine induced killer (CIK) cells.
Methods: Lymphocytes isolated from peripheral blood of leukemic children were induced with γ- interferon
(IFN-γ), CD3McAb and interluki-2 (IL-2), and co-cultured with dendritic cells (DCs) to generate DC-CIK cells.
The morphology and immunophenotype of these cells were determined by a light microscopy and flow
cytometry, respectively. IL-2 and IFN-γ levels released by DC-CIK cells were quantified by ELISA. Cytotoxicity
of DC-CIK cells against leukemia cell lines was measured by MTT assay. FCM was used to detect
CD4+CD25+Treg cells, while RT-PCR and Western blot were used to determine mRNA and protein expressions
of Foxp3 and GATA3 in DC-CIK cells treated with T-bet monoclonal antibody.
Findings: Induced DC-CIK cells were regular, round and transparent with variable cell volume and cellular
aggregation. The main effector cells in this population were CD3+CD8+ cells and CD3+CD56+ cells. We
demonstrated a time dependent increase in IL-2 and IFN-γ levels after induction. DC-CIK cells were cytotoxic
to B95 cells, Jhhan cells and M07e cells, with the highest cytotoxicity towards B95 cells. Treatment with
mouse anti-human T-bet monoclonal antibody resulted in an increase in the proportion of CD4+CD25+Treg
cells and elevation of Foxp3 and GATA3 mRNA and protein levels.
Conclusion: DC-CIK cells induced with cytokines were strongly cytotoxic towards a number of cancer cell
lines. Foxp3 and GATA3 were implicated in the T-bet mediated anti-neoplastic effects of DC-CIK cells via
activation of the Th1 pathway and suppression of the Th2 and Treg pathways.