Th1-Polarizing Capacity of Clinical-Grade Dendritic Cells Is Triggered by Ribomunyl but Is Compromised by PGE2

Abstract

The maturation state of (monocyte-derived) dendritic cells (DCs) determines the type of T-cell response. Currently, several maturation cocktails are used in clinical trials, most commonly a cocktail of TNF-alpha, PGE2, IL-1beta, and IL-6. The authors studied DC phenotype and functional ability to stimulate TH1 responses after maturation with different cocktails employing clinically approved agents. DCs were stimulated with the microbial agent Ribomunyl combined with IFN-gamma and various inflammatory cytokine cocktails: TNF-alpha/IL-1beta/IFN-gamma and TNF-alpha/PGE2 combined with monocyte-conditioned medium (MCM) or IL-1beta/IL-6. Regardless of the maturation cocktail used, all DCs possessed the characteristic phenotype of mature, migratory DCs (high expression of CD40, CD80, CD83, CD86, CCR7, MHC class I and MHC class II). Ribomunyl/IFN-gamma matured DCs produced high IL-12p70 levels, whereas other maturation stimuli did not. Even more striking, restimulation of Ribomunyl IFN-gamma mDCs with CD40-activating antibody reactivated IL-12p70 production. No IL-12p70 could be detected when DCs were stimulated with TNF-alpha/PGE2 combined with MCM or IL-1beta/IL-6, presumably by suppression by PGE2. Restimulation of these DCs with CD40-activating antibody failed to activate IL-12p70 production. Moreover, low levels of IL-10 were observed, possibly indicating inhibition of TH1-cell responses. Indeed, T cells stimulated with these DCs produced high levels of type 2 cytokine IL-5 and outgrowth of CD4CD25 T cells. This study shows that DC maturation with cytokine cocktails different from those most commonly used could be beneficial for immunotherapy trials in cancer patients.

Immunologic and Clinical Effects of Injecting Mature Peptide-Loaded Dendritic Cells by Intralymphatic and Intranodal Routes in Metastatic Melanoma Patients

“…This cytokine is known to play a critical role in driving CD4 + T cells to TH1 polarization, a property essential for the development of T-cell -mediated antitumor response. As a matter of fact, dendritic cells matured with Ribomunyl and IFN-g and cocultured with T cells are known to induce TH1-characteristic cytokines (12,16,17). Third, to minimize the risk of poor migration of dendritic cells toward lymph nodes, the first cell injection was done into a lymphatic vessel.…”

Increased Tumor-Specific CD8+ T Cell Induction by Dendritic Cells Matured with a Clinical Grade TLR-Agonist in Combination with IFN-γ

“…One attractive option involves the use of microbial ligands and Toll-like receptor (TLR) agonists in particular (17). The TLR2/4 agonist FMKp in combination with IFN-y has been shown to exert powerful DC activation signals leading to high IL-12 secretion, Th1 skewing and cytotoxic T cell induction (18)(19). Numerous studies have pointed towards the necessity of PRR triggering (TLR stimuli in particular) in DC maturation to obtain potent T cell responses, and this was correlated with potent anti-tumour responses in animal models (20)(21)(22)(23).…”

IRX-2, a Novel In Vivo Immunotherapeutic, Induces Maturation and Activation of Human Dendritic Cells In Vitro

“…This contrasts to the MCM-mimic cocktail which has been shown to be deficient at stimulating IL-12p70 secretion from matured DC. 32,[40][41][42] We further demonstrated that IRX-2-treated DC are more efficient at stimulating T cells as shown by enhanced proliferation in allogeneic MLR reactions. Moreover, IRX-2 was shown to increase the expression of ICAM-1 (CD54).…”