Background: Dendritic cells (DCs) are professional antigen presenting cells that have an important role in the initiation of immune response. The use of maturation factors in dendritic cell differentiation provides a promising approach in immunotherapy.
Objective: In this study, we compared tumor necrosis factor-α, polyribocytidylic acid, lipopolysacharide and CpG oligonucleotides in inducing dendritic cell maturation.
Methods: We generated immature dendritic cells with GM-CSF in combination with IL-4 from peripheral blood mononuclear adherent cells and used tumor necrosis factor-α, polyribocytidylic acid, lipopolysacharide and CpG for the induction of dendritic cell maturation. CD83 maturation marker on the dendritic cells was analyzed by flowcytometry after 7 days. In addition, mixed leukocyte reaction between dendritic cells and T cells was performed by MTT proliferation assay.
Results: Flow cytometry results demonstrated a comparable high level of CD83 expression on the mature dendritic cells generated by TNF-α, CpG, Poly I:C, and LPS treatment of the immature dendritic cells. However, a significantly poorer proliferation of lymphocytes cocultured with the Poly I:C-treated DCs was observed compared to the CpG-treated DCs in mixed leukocyte reaction (p=0.026). Conversely, a significantly stronger proliferation of lymphocytes was observed when cocultured with TNF-α-treated DCs compared to the LPS-treated DCs (p=0.025).
Conclusion: Our results indicated that all of studied maturation inducing factors can be used in DC maturation but TNF-α and CpG were the preferred in vitro maturation factors. It is concluded that maturation of dendritic cells by CpG motif and TNF-α can be used to regulate immune responses.