Prostaglandin E2 in a TLR3- and 7/8-agonist-based DC maturation cocktail generates mature, cytokine-producing, migratory DCs but impairs antigen cross-presentation to CD8+ T cells

Abstract

Mature dendritic cells (DCs) represent cellular adjuvants for optimal antigen presentation in cancer vaccines. Recently, a combination of prostaglandin E 2 (PGE 2) with Toll-like receptor agonists (TLR-P) was proposed as a new standard to generate superior cytokine-producing DCs with high migratory capacity. Here, we compare TLR-P DCs with conventional DCs matured only with the proinflammatory cytokines TNFα and IL-1ß (CDCs), focussing on the interaction of resulting DCs with CD8 + T-cells. TLR-P matured DCs showed elevated expression of activation markers such as CD80 and CD83 compared to CDCs, together with a significantly higher migration capacity. Secretion of IL-6, IL-8, IL-10, and IL-12 was highest after 16 h in TLR-P DCs, and only TLR-P DCs secreted active IL-12p70. TLR-P DCs as well as CDCs successfully primed multifunctional CD8 + T-cells from naïve precursors specific for the peptide antigens Melan-A, NLGN4X, and PTP with comparable priming efficacy and T-cell receptor avidity. CD8 + T-cells primed by TLR-P DCs showed significantly elevated expression of the integrin VLA-4 and a trend for higher T-cell numbers after expansion. In contrast, TLR-P DCs displayed a substantially reduced capability to cross-present CMVpp65 protein antigen to pp65-specific T cells, an effect that was dose-dependent on PGE 2 during DC maturation and reproducible with several responder T-cell lines. In conclusion, TLR-P matured DCs might be optimal presenters of antigens not requiring processing such as short peptides. However, PGE 2 seems less favorable for maturation of DCs intended to process and cross-present more complex vaccine antigens such as lysates, proteins or long peptides. Keywords Dendritic cells • Cancer vaccines • Prostaglandin E 2 • TLR agonists • Tumor-specific CD8 + T cells Abbreviations 7-AAD 7-Aminoactinomycin BDCA-3 Blood-derived dendritic cell antigen 3 CCL Chemokine ligand CCR Chemokine receptor CDC Conventional, cytokine matured DC (here, matured with TNFα, IL-1ß) COX-2 Cyclooxygenase 2 CMV Cytomegalo virus DC Dendritic cell FSC Forward scatter GMP Good manufacturing practice MACS Magnetic activated cell sorting MFI Mean fluorescence index TLR-P-DC Monocyte-derived DC, matured with TLR3 + 7/8 agonists and PGE2 MDSC Myeloid-derived suppressor cells NLGN4X Neuroligin-4, X-linked PGE2 Prostaglandin E2 SSC Sideward scatter TCR T-cell receptor TLR Toll-like receptor Note on previous publication Parts of this paper have been presented at a scientific conference: 14th Annual meeting of the association for cancer immunotherapy (CIMT), 10-12th May 2016, Mainz, Germany Abstract #O23 (Poster).

Toll-Like Receptor 3 in Solid Cancer and Therapy Resistance

“…Gierlich et al have recently evidenced the importance of Poly(I:C) in combination with prostaglandin E2 and TLR7/8 agonist R848, in the maturation of DCs, which have a role in antigen presentation in cancer vaccines. The study showed that these DCs have high migratory ability and priming efficacy, together with increased cytokines production [67].…”

Cyclooxygenase-Derived Prostaglandin E2 Drives IL-1–Independent Mycobacterium bovis Bacille Calmette-Guérin–Triggered Skin Dendritic Cell Migration to Draining Lymph Node

“…In contrast, the presence of PGE 2 in such cocktails may impair other DC functions. In particular, PGE 2 may limit cytokine production ( 30 , 33 ) and in a dose-dependent manner reduce cross-presentation ( 34 ). High levels of PGE 2 stimulation may even suppress DC migration ( 35 ).…”

The Role of Toll-like Receptor Agonists and Their Nanomedicines for Tumor Immunotherapy

“…Furthermore, the combination of Poly(I:C) and R848 with E7 DNA can induce the enormous regression of tumors, circulating antigen-specific IFN-γ and non-specific intratumoral IL-12 [67]. Similarly, Toll-like receptor agonists (TLR-P), Poly(I:C)/R848/PGE2, contribute to DCs with mature phenotypes and a brilliant ability to migrate and secrete cytokines, especially IL-12p70 production [68]. In the cancer therapy realm, work by Caisova and coworkers optimized therapeutic mixtures based on welldefined compounds, including the biocompatible anchor for the membranes (BAM) of mannan anchored to the surface of tumor cells, R848, poly(I:C), and lipoteichoic acid (LTA), leading to the eradication of advanced stage progressive melanoma in 83% of mice, the acquisition of resistance to tumor recurrence, and potential anti-metastatic effect [69].…”