In Vitro–expanded Antigen-specific Regulatory T Cells Suppress Autoimmune Diabetes

TLDR

The low number, anergic phenotype, and diverse antigen specificity of CD4⁺CD25⁺ regulatory T cells hinder their therapeutic use in autoimmunity and transplant rejection. This study develops a robust method to expand antigen‑specific Tregs from autoimmune‑prone non‑obese diabetic mice. Purified CD4⁺CD25⁺ Tregs were expanded up to 200‑fold in less than two weeks in vitro using anti‑CD3, anti‑CD28, and IL‑2. The expanded Tregs display a classical phenotype, suppress effector T cells in vitro and in vivo, and small numbers of antigen‑specific Tregs can reverse diabetes after onset, indicating a novel cellular immunotherapy for autoimmunity.

Abstract

The low number of CD4+ CD25+ regulatory T cells (Tregs), their anergic phenotype, and diverse antigen specificity present major challenges to harnessing this potent tolerogenic population to treat autoimmunity and transplant rejection. In this study, we describe a robust method to expand antigen-specific Tregs from autoimmune-prone nonobese diabetic mice. Purified CD4+ CD25+ Tregs were expanded up to 200-fold in less than 2 wk in vitro using a combination of anti-CD3, anti-CD28, and interleukin 2. The expanded Tregs express a classical cell surface phenotype and function both in vitro and in vivo to suppress effector T cell functions. Most significantly, small numbers of antigen-specific Tregs can reverse diabetes after disease onset, suggesting a novel approach to cellular immunotherapy for autoimmunity.