Maternal Type 1 Diabetes Reduces Autoantigen-Responsive CD4⁺ T Cells in Offspring

Area of Science:

• Immunology
• Endocrinology
• Genetics

Background:

• Autoimmunity against pancreatic β-cell autoantigens characterizes childhood type 1 diabetes (T1D).
• Genetic susceptibility and autoantibodies against (pro)insulin are typical in T1D development.
• Offspring of mothers with T1D exhibit protection against this autoimmune process.

Purpose of the Study:

• To investigate if maternal T1D confers improved neonatal immune tolerance against (pro)insulin.
• To understand the mechanisms behind the protective effect observed in offspring of mothers with T1D.

Main Methods:

• Compared immune responses in offspring of mothers with T1D versus offspring of fathers or siblings with T1D.
• Analyzed cord blood CD4+ T-cell responses to proinsulin and insulin.
• Assessed the inflammatory profile and regulatory capacity of T cells at 9 months of age.
• Examined CpG methylation of the INS gene in cord blood mononuclear cells.

Main Results:

• Offspring of mothers with T1D demonstrated reduced CD4+ T-cell responses to proinsulin and insulin in cord blood.
• These individuals showed a less inflammatory profile in proinsulin-responsive CD4+ T cells.
• Improved regulation of CD4+ T-cell responses to proinsulin was observed at 9 months of age.
• A modest reduction in INS gene CpG methylation was noted in offspring with a susceptible INS genotype.

Conclusions:

• Maternal T1D environment enhances neonatal immune tolerance to the autoantigen (pro)insulin.
• This improved tolerance is associated with reduced T-cell reactivity and enhanced regulatory mechanisms.
• Findings suggest a protective role of maternal T1D in modulating the offspring's immune response to insulin autoantigens.