A humanized mouse model of autoimmune insulitis

Area of Science:

• Immunology
• Endocrinology
• Transplantation Biology

Background:

• Current type 1 diabetes research models, like the NOD mouse, often fail to replicate human disease mechanisms.
• A critical need exists for an in vivo system to study the development and onset of human autoimmune diabetes.

Purpose of the Study:

• To characterize a novel in vivo system for studying human autoimmune diabetes using human CD4(+) T cells and a specialized mouse model.
• To assess the ability of autoantigen-pulsed human CD4(+) T cells to induce pancreatic beta-cell destruction in vivo.

Main Methods:

• Human CD4(+) T cells were pulsed with autoantigen-derived peptides.
• These pulsed cells were injected into NOD-Scid Il2rg(-/-) mice expressing the human HLA-DR4 transgene.
• Islet infiltration, insulitis, insulin staining, and levels of beta-cell-derived DNA in the bloodstream were analyzed.

Main Results:

• Injection of as few as 0.5 × 10(6) antigen-pulsed human CD4(+) T cells led to T cell infiltration of mouse islets.
• Diabetic donor T cells induced significantly greater insulitis and reduced insulin staining compared to healthy donor cells.
• Reduced insulin staining correlated with increased levels of demethylated beta-cell-derived DNA in the bloodstream.

Conclusions:

• This study demonstrates that autoantigen-reactive human CD4(+) T cells can induce targeted destruction of pancreatic beta cells in a humanized mouse model.
• The developed model provides a valuable platform for investigating the mechanisms underlying human type 1 diabetes induction and progression.