IFN-γ Enhances T_H1 Polarisation of Monocyte-derived Dendritic Cells Matured with Clinical-grade Cytokines Using Serum-free Conditions

Abstract

Using serum-free conditions, human monocyte-derived dendritic cells (MoDCs) tend to mature insufficiently in a T_H1-polarizing direction under approved and standardized clinical conditions. However, for the initiation of an efficient tumour antigen-specific cytotoxic T-cell response, the induction of a distinct T_H1 response is favourable. Therefore, to improve T_H1 polarisation, the influence of interferon-gamma (IFN-γ) on the maturation of MoDCs was investigated with clinical-grade cytokines or lipopolysaccharide (LPS) in serum-free medium focusing on the viability, phenotypic characteristics, cytokine profile and restimulating capacities. As in previous research, we confirmed that in respect of viability and phenotypic characteristics, cytokine cocktails consisting of tumour necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6 and prostaglandin (PG) E₂, mature MoDCs most efficiently. However, these cytokine-matured MoDCs secreted relatively high levels of IL-10 and only low levels of IL-12p70. Remarkably, if IFN-γ was added, significantly lower levels of IL-10 concomitant with higher levels of IL-12p70 could be detected. Pretreatment with IFN-γ did not improve the phenotypic characteristics nor the T_H1 polarisation of MoDCs. Nevertheless, MoDCs matured with clinical-grade cytokines and IFN-γ could be re-stimulated most effectively with IFN-γ. In conclusion, our work demonstrates that addition of INF-γ to clinical-grade cytokine cocktails readily matures MoDCs and enhances their T_H1 polarisation efficiently under serum-free conditions.