Engineering the lymph node environment promotes antigen-specific efficacy in type 1 diabetes and islet transplantation

Antigen-specific tolerance represents a promising strategy to treat type 1 diabetes and islet allograft rejection. Here, the authors deliver immune signals to lymph nodes to promote antigen-specific regulatory T cells and prevent disease in models of type 1 diabetes and allogenic islet transplantation. Antigen-specific tolerance is a key goal of experimental immunotherapies for autoimmune disease and allograft rejection. This outcome could selectively inhibit detrimental inflammatory immune responses without compromising functional protective immunity. A major challenge facing antigen-specific immunotherapies is ineffective control over immune signal targeting and integration, limiting efficacy and causing systemic non-specific suppression. Here we use intra-lymph node injection of diffusion-limited degradable microparticles that encapsulate self-antigens with the immunomodulatory small molecule, rapamycin. We show this strategy potently inhibits disease during pre-clinical type 1 diabetes and allogenic islet transplantation. Antigen and rapamycin are required for maximal efficacy, and tolerance is accompanied by expansion of antigen-specific regulatory T cells in treated and untreated lymph nodes. The antigen-specific tolerance in type 1 diabetes is systemic but avoids non-specific immune suppression. Further, microparticle treatment results in the development of tolerogenic structural microdomains in lymph nodes. Finally, these local structural and functional changes in lymph nodes promote memory markers among antigen-specific regulatory T cells, and tolerance that is durable. This work supports intra-lymph node injection of tolerogenic microparticles as a powerful platform to promote antigen-dependent efficacy in type 1 diabetes and allogenic islet transplantation.

Automated summary

The authors have successfully promoted the production of antigen-specific regulatory T cells and prevented the occurrence of type 1 diabetes and allogenic islet transplantation by delivering immune signals to lymph nodes. Antigen-specific tolerance is an important goal in experimental immunotherapy for autoimmune diseases and organ transplantation, as it can selectively inhibit harmful immune responses without compromising protective immunity. However, the current challenge lies in the ineffective control over immune signal targeting, which limits the efficacy and causes non-specific suppression.