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Open Access Research article

Local delivery of AAV2-CTLA4IgG decreases sialadenitis and improves gland function in the C57BL/6.NOD-Aec1Aec2 mouse model of Sjögren's syndrome

Hongen Yin1, Cuong Q Nguyen2, Yuval Samuni1, Toshimitsu Uede3, Ammon B Peck2 and John A Chiorini1*

Author Affiliations

1 Molecular Physiology and Therapeutics Branch, National Institute of Dental and Cranial Research, National Institutes of Health, 10 Center Drive, MSC1190, Bethesda, MD 20892, USA

2 Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida

3 Section of Immunopathogenesis, Institute of Immunological Science, Hokkaido University, Sapporo, Hokkaido 060, Japan

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Arthritis Research & Therapy 2012, 14:R40  doi:10.1186/ar3753

Published: 27 February 2012

Abstract

Introduction

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a key negative costimulatory molecule that displays a wide range of anti-inflammatory properties and is currently approved to treat rheumatoid arthritis as a recombinant fusion protein (CTLA4IgG). To better understand the role of CTLA4IgG in primary Sjögren's syndrome (pSS), we generated a recombinant adeno-associated virus vector serotype 2 (AAV2) expressing a chimera of mouse CTLA-4 fused with a human immunoglobulin (AAV2-CTLA4IgG) and observed the effect of this molecule in C57BL/6.NOD-Aec1Aec2 mice, an animal model of pSS.

Methods

A recombinant adeno-associated virus-2 (AAV-2) vector was constructed encoding a CTLA4IgG fusion protein. The AAV2-CTLA4IgG vector and an AAV2 control vector encoding beta galactosidase (LacZ) were administered by retrograde cannulation of the submandibular glands of C57BL/6.NOD-Aec1Aec2 mice. Protein expression was measured by ELISA and salivary glands were assessed for inflammation and activity.

Results

Recombinant CTLA4IgG blocked B7 expression on macrophages in vitro. In vivo, localized expression of CTLA4IgG in the salivary glands of C57BL/6.NOD-Aec1Aec2 mice inhibited the loss of salivary gland activity and decreased T and B cell infiltration as well as dendritic cells and macrophages in the glands compared with control mice. In addition a decrease in several proinflammatory cytokines and an increase in transforming growth factor beta-1 (TGF-β1) expression were also observed.

Conclusions

These data suggest expression of CTLA4IgG in the salivary gland can decrease the inflammation and improve the xerostomia reported in these mice.

Keywords:
Sjögren's Syndrome; salivary gland dysfunction; adeno-associated virus (AAV); CTLA4IgG fusion protein; prevention