Human Tolerogenic Dendritic Cells Generated with Protein Kinase C Inhibitor Are Optimal for Regulatory T Cell Induction-a Comparative Study

Endy Adnan¹, Hitoshi Hasegawa², Takuya Matsumoto¹, Jun Ishizaki¹, Sachiko Onishi¹, Koichiro Suemori¹ and Masaki Yasukawa¹, ¹Department of Hematology, Clinical Immunology, and Infectious Diseases, Ehime University Graduate School of Medicine, Toon, Japan, ²Department of Hematology, Clinical Immunology and Infectious Diseases, Ehime University Graduate School of Medicine, Toon, Japan

Meeting: 2014 ACR/ARHP Annual Meeting

Keywords: Dendritic cells, regulatory cells and tolerance

Session Information

Title: Innate Immunity and Rheumatic Disease: Mediators, Cells and Receptors

Session Type: Abstract Submissions (ACR)

Background/Purpose

Tolerogenic dendritic cells (tDCs) are a promising tool for autoimmune diseases, transplantation and allergy. Actually, tDCs have been tried for the therapy of rheumatoid arthritis and type 1 diabetes. To date, immunomodulatory DCs are prepared from monocytes for in vitro experiments by using various agents. Previously, we generated stable tDCs with protein kinase C inhibitor (PKCI) in human and mouse and PKCI-tDCs prevented graft-versus-host disease in a murine model (J Immunol 191: 2247, 2013). The following functional characteristics are required for clinically applicable tDCs: efficient induction of functional regulatory T cells (Treg); CCR7-dependent migration; and stability under proinflammatory conditions. In this study, to select the optimal agent for clinically applicable tDCs, we compared the clinical-grade tDCs generated with various agents.

Methods

We compared tDCs generated with the following agents; vitamin D3 (Vit D3), dexamethasone (Dexa), bisindolylmaleimide I (PKCI), PPAR gamma plus retinoic acid (PPAR+RA), rapamicin (Rapa), IL-10, and TGF-beta. tDCs were prepared by adding these agents prior to the induction of maturation using TNF-alpha, IL-1beta and PGE2. We evaluated the effects of each agent on phenotype, CCR7-dependent migration, cytokine production, phagocytosis, stability, T-cell suppression, and induction of IL-10-producing T cells and functional Foxp3⁺ Treg cells.

Results

All tDCs except Rapa-tDCs showed an immature or semi-mature phenotype, whereas the phenotype of Rapa-tDCs resembled that of mature DCs. PKCI-tDCs, TGF-tDCs and Rapa-tDCs had moderate and high CCR7 expression, whereas tDCs generated with PPAR+RA, Vit D3, Dexa or IL-10 had very low CCR7 expression. IL-10 production by IL-10-tDCs and PKCI-tDCs was high. Immature DCs (iDCs) and PKCI-tDCs showed high production of TGF-beta. Functionally, iDCs, PKCI-tDCs, PPAR+RA-tDCs, Vit D3-tDCs and IL-10-tDCs strongly suppressed T-cell activation, whereas Dexa-tDCs, TGF-tDCs and Rapa-tDCs weakly suppressed. All tDCs showed phagocytic ability and stable tolerogenic properties under proinflammatory conditions. From these findings, PKCI-tDCs showed moderate expression of CCR7, leading to migrate toward CCR7 ligands, maintained stability, and strongly suppressed T-cell activation by generating IL-10-producing T cells and functional Foxp3⁺ Treg cells.

Conclusion

PKCI-tDCs appear to be optimal for clinically applicable tDCs. We expect that PKCI-tDCs are useful for tolerance-inducing therapies.

Disclosure:

E. Adnan,
None;

H. Hasegawa,
None;

T. Matsumoto,
None;

J. Ishizaki,
None;

S. Onishi,
None;

K. Suemori,
None;

M. Yasukawa,
None.

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