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

Using serum-free conditions, human monocyte-derived dendritic cells (MoDCs) tend to mature insufficiently in a TH1-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 TH1 response is favourable. Therefore, to improve TH1 polarisation, the influence of interferon-γ (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-α (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 TH1 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 TH1 polarisation efficiently under serum-free conditions

Combination systemic therapies with immune checkpoint inhibitors in pancreatic cancer: overcoming resistance to single-agent checkpoint blockade

Abstract Immune checkpoint inhibitors have demonstrated broad single-agent antitumor activity and a favorable safety profile that render them attractive agents to combine with other systemic anticancer therapies. Pancreatic cancer has been fairly resistant to monotherapy blockade of programmed cell death protein 1 receptor, programmed death ligand 1, and cytotoxic T-lymphocyte associated protein 4. However, there is a growing body of preclinical evidence to support the rational combination of checkpoint inhibitors and various systemic therapies in pancreatic cancer. Furthermore, early clinical evidence has begun to support the feasibility and efficacy of checkpoint inhibitor-based combination therapy in advanced pancreatic cancer. Despite accumulating preclinical and clinical data, there remains several questions as to the optimal dosing and timing of administration of respective agents, toxicity of combination strategies, and mechanisms by which immune resistance to single-agent checkpoint blockade are overcome. Further development of biomarkers is also important in the advancement of combination systemic therapies incorporating checkpoint blockade in pancreatic cancer. Results from an impressive number of ongoing prospective clinical trials are eagerly anticipated and will seek to validate the viability of combination immuno-oncology strategies in pancreatic cancer