Multicomponent Plasmid Protects Mice From Spontaneous Autoimmune Diabetes

Area of Science:

• Immunology
• Endocrinology
• Gene Therapy

Background:

• Type 1 diabetes involves autoimmune destruction of insulin-producing beta-cells, necessitating lifelong insulin therapy.
• Current treatments lack disease-modifying capabilities, and future immunotherapies must avoid broad immune suppression.

Purpose of the Study:

• To develop and evaluate a novel plasmid-based immunotherapy for preventing autoimmune diabetes.
• To assess the efficacy of antigen-specific tolerization using preproinsulin2 and immune-modulatory cytokines.

Main Methods:

• A novel plasmid encoding preproinsulin2 and cytokines (transforming growth factor-beta-1, IL-10, IL-2) was developed.
• The plasmid's efficacy was tested in non-obese diabetic mice via intramuscular or subcutaneous injections.
• Immune responses, including cytokine levels and myeloid cell populations, were analyzed.

Main Results:

• The plasmid therapy achieved near-complete prevention of autoimmune diabetes in mice.
• Efficacy was dependent on both preproinsulin2 and the cytokine combination, indicating antigen-specific tolerization.
• Intramuscular treatment increased endogenous IL-10 and modulated myeloid cells without global immunosuppression.

Conclusions:

• This plasmid-based immunotherapy demonstrates potential for inducing self-tolerance in individuals at risk for type 1 diabetes.
• The study identifies relevant biomarkers for future clinical trials.
• A modified plasmid is being evaluated in a Phase 1 clinical trial (NCT04279613).