Vaccination with a co-expression DNA plasmid containing GAD65 fragment gene and IL-10 gene induces regulatory CD4(+) T cells that prevent experimental autoimmune diabetes.

Abstract

BACKGROUND:

The non-obese diabetic (NOD) mouse is a commonly used animal model for studying type 1 diabetes (T1D). The aims of our study were to explore the diabetes-preventive effect in NOD mice and the potential mechanisms of an optimized co-expression DNA vaccine containing GAD65 fragment gene with the IL-10 gene (SGAD65190-315 /IL-10).

METHODS:

Female NOD mice at the age of 3-4 weeks old were randomly divided into two groups and received intra-muscular injection of either blank pBudCE4.l vector (n = 34) or pBudCE4.l carrying the SGAD65190-315 /IL-10 (n = 32). The incidence of diabetes was monitored up to 30 weeks of age. The severity of insulitis, apoptosis rate of β cells and relevant mechanisms were examined.

RESULTS:

Administration with SGAD65190-315 /IL-10 blocked the onset of autoimmune diabetes in NOD mice, significantly suppressed islet inflammation, inhibited the apoptosis of islet β cells, induced immune tolerance to autoantigen GAD65 and proinsulin and shifted the Th1/Th2 balance towards Th2. More importantly, the frequencies of CD4(+) CD25(+) Foxp3(+) regulatory T cells (Tregs) in the spleen and pancreatic lymph nodes in vaccine-immunized mice were significantly increased, and these Tregs were GAD65-reactive. In addition, Treg depletion by anti-CD25 mAb administration abolished the protective effects of SGAD65190-315 /IL-10 on diabetes and insulitis. Moreover, depletion of CD4(+) CD25(+) T cells using magnetic-activated cell sorting impaired the protective effect of SGAD65190-315 /IL-10 vaccination on adoptive transfer of diabetes.

CONCLUSIONS:

Our data suggested that SGAD65190-315 /IL-10 DNA vaccine had protective effects on T1D by upregulating autoantigen-reactive Tregs. Our findings may provide a novel preventive therapy for T1D. Copyright © 2016 John Wiley & Sons, Ltd.

• Authors: Xinyuan Liu, Song Zhang, Xia Li, Peilin Zheng, Fang Hu, Zhiguang Zhou
• Journal: Diabetes/metabolism research and reviews (Diabetes Metab Res Rev) Vol. 32 Issue 6 Pg. 522-33 (09 2016) ISSN: 1520-7560 [Electronic] England
• PMID: 26797873 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2016 John Wiley & Sons, Ltd.

Chemical References

• Forkhead Transcription Factors
• IL10 protein, mouse
• Vaccines, DNA
• Interleukin-10
• Glutamate Decarboxylase
• glutamate decarboxylase 2

Topics

• Adoptive Transfer
• Animals
• Autoimmune Diseases (genetics, immunology, prevention & control)
• CD4-Positive T-Lymphocytes (immunology)
• Diabetes Mellitus, Experimental (genetics, immunology, prevention & control)
• Female
• Forkhead Transcription Factors (genetics, metabolism)
• Glutamate Decarboxylase (genetics)
• Humans
• Immune Tolerance
• Interleukin-10 (genetics)
• Lymphocyte Activation
• Mice
• Mice, Inbred NOD
• Mice, SCID
• Plasmids (administration & dosage)
• T-Lymphocytes, Regulatory (immunology)
• Vaccination
• Vaccines, DNA (administration & dosage)