Allogeneic Mature Human Monocyte-Derived Dendritic Cells Generate Superior Alloreactive Regulatory T Cells in an IL-2-Independent Manner

N. Litjens,¹ K. Boer,¹ J. Zuijderwijk,¹ M. Klepper,¹ A. Peeters,¹ E. Prens,² W. Verschoor,¹ R. Kraaijeveld,¹ Z. Ozgur,³ M. van den Hout-van Vroonhoven,³ W. van IJcken,³ C. Baan,¹ M. Betjes.¹

¹Internal Medicine, Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, Netherlands
²Dermatology and Rheumatology, Erasmus Medical Center, Rotterdam, Netherlands
³Erasmus Center for Biomics, Erasmus Medical Center, Rotterdam, Netherlands.

Meeting: 2015 American Transplant Congress

Abstract number: 424

Keywords: Alloantigens, Immunosuppression, T cells

Session Information

Session Name: Concurrent Session: Transplant Tolerance: Animal Models II

Session Type: Concurrent Session

Date: Tuesday, May 5, 2015

Session Time: 2:15pm-3:45pm

Presentation Time: 3:15pm-3:27pm

Location: Room 118-C

Introduction

Expansion of antigen (Ag)-specific natural occurring regulatory T cells (nTregs) is required to obtain sufficient numbers of cells for cellular immunotherapy. In this study, different allogeneic stimuli were studied for their capacity to generate functional alloantigen-specific nTregs.

Methods

A highly enriched nTreg-fraction (CD4+CD25brightCD127- T cells) was alloantigen-specific expanded using HLA-mismatched immature, mature monocyte-derived dendritic cells (moDC) or peripheral blood mononuclear cells (PBMC). The allogeneic mature moDC-expanded nTregs were fully characterized by analysis of the demethylation status within the TSDR of the FOXP3 gene and the expression of both protein and mRNA of FOXP3, HELIOS, CTLA4 and cytokines. In addition, the antigen-specific suppressive capacity of these expanded nTregs was tested.

Results

Allogeneic mature moDC were superior in inducing nTreg-expansion compared to immature moDC or PBMC. Remarkably, the presence of exogenous IL-15, but not IL-2, was needed for optimal mature moDC-induced nTreg-expansion. Allogeneic mature moDC-expanded nTregs were potent suppressors of alloantigen-induced proliferation. Even at low ratios (<1:320), these expanded nTregs still efficiently suppressed alloAg-induced, but hardly the completely HLA-mismatched-Ag-(3rdP)-induced, proliferation. Mature moDC-expanded nTregs were highly demethylated at the TSDR within the FOXP3 gene and highly expressed of FOXP3, HELIOS and CTLA4. In addition, hardly any expanded nTregs produced IL-17 whereas a minority of nTregs produced IL-10, IL-2, IFN-gamma and TNF-alpha. Next generation sequencing of mRNA of moDC-expanded nTregs revealed a strong induction of Treg-associated mRNAs.

Conclusions

Human allogeneic mature moDC are highly efficient, IL-2-independent, stimulator cells for expansion of stable alloantigen-specific nTregs with superior suppressive function. This opens a new avenue for using Tregs as source for cellular immunotherapy in kidney transplantation.

To cite this abstract in AMA style:

Litjens N, Boer K, Zuijderwijk J, Klepper M, Peeters A, Prens E, Verschoor W, Kraaijeveld R, Ozgur Z, IJcken Wvan, Baan C, Betjes M. Allogeneic Mature Human Monocyte-Derived Dendritic Cells Generate Superior Alloreactive Regulatory T Cells in an IL-2-Independent Manner [abstract]. Am J Transplant. 2015; 15 (suppl 3). https://atcmeetingabstracts.com/abstract/allogeneic-mature-human-monocyte-derived-dendritic-cells-generate-superior-alloreactive-regulatory-t-cells-in-an-il-2-independent-manner/. Accessed May 9, 2025.

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