Dendritic cell immunoreceptor: A聽novel receptor for intravenous immunoglobulin mediates induction of regulatory T cells

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• 作者：Amir H. Massoud ; PhD^a ; ^b ; Madelaine Yona ; BSc^a ; Di Xue ; BSc^a ; Fazila Chouiali ; MSc^a ; Haydar Alturaihi ; MSc^b ; Aidan Ablona ; BSc^a ; Walid Mourad ; PhD^b ; Ciriaco A. Piccirillo ; PhD^c ; Bruce D. Mazer ; MD^a ; ^{bruce.mazer@mcgill.ca" class="auth_mail}
• 关键词：Intravenous immunoglobulin ; dendritic cells ; regulatory T cells ; immune modulation ; asthma
• 刊名：Journal of Allergy and Clinical Immunology
• 出版年：March, 2014
• 年：2014
• 卷：133
• 期：3
• 页码：853-863.e5
• 全文大小：4377 K

文摘

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Background

Intravenous immunoglobulin (IVIg) is a polyclonal IgG preparation with potent immunomodulating properties. Our laboratory demonstrated that IVIg significantly increases numbers of forkhead box protein 3-positive regulatory T (Treg) cells through generation of tolerogenic dendritic cells (DCs) in an allergic airways disease model.

Objective

We sought to investigate potential receptors on DCs聽mediating these events.

Methods

C57BL/6 mice were either sensitized to ovalbumin (OVA) intraperitoneally or through adoptive transfer of OVA-primed DCs and then challenged with intranasal OVA. IVIg聽was fractionated into sialic acid-enriched IVIg (SA-IVIg) and sialic acid-depleted IVIg (non-SA-IVIg). Dendritic cell immunoreceptor (DCIR) constructs in CHO cells or on DCs were examined by using fluorescent microscopy and flow cytometry.

Results

Administration of SA-IVIg, but not non-SA-IVIg, to OVA-sensitized and OVA-challenged mice induced Treg cells and attenuated airway hyperresponsiveness (AHR) and inflammation comparably with IVIg. Bone marrow-derived dendritic cells cultured with SA-IVIg or IVIg adoptively transferred to mice before OVA challenge induced Treg cells and inhibited AHR. IVIg-treated bone marrow-derived dendritic cells from Fc纬 receptor knockout mice inhibited AHR, suggesting IVIg鈥檚 action was not caused by Fc纬 receptor-mediated events. Fluorescently labeled IVIg or SA-IVIg bound DCs and colocalized specifically to the C-type lectin DCIR. IVIg binding to DCIR induced phosphorylation of Src homology domain 2-containing protein tyrosine phosphatase (SHP) 2 and Src homology domain 2-containing inositol phosphatase 1 (SHIP-1) and internalization of IVIg into DCs. Inhibition of IVIg binding to DCIR by small interfering RNA completely blocked induction of Treg cells. Inhibition of SHP-2 or abrogation of IgG internalization through clatherin inhibitors rendered IVIg ineffective.

Conclusions

IVIg alleviates allergic airways disease through interaction of SA-IgG with DCIR. DCIR is a novel receptor for IVIg, mediating interaction of innate and adaptive immunity in tolerogenic responses.