Engineering red blood cells for antigen-specific immune tolerance and personalized therapy of autoimmune diseases

Current therapies for autoimmune diseases largely rely on broad-spectrum immunosuppressants and biologics, which indiscriminately deplete T or B cells. These approaches are largely constrained by systemic immunosuppression and off-target toxicities. Achieving durable, antigen-specific immune tolerance while preserving protective immunity against pathogens remains a long-standing goal in clinical practice. Here, we present a modular red blood cell (RBC)-based platform that induces antigen-specific tolerance through strain-promoted azide-alkyne cycloaddition (SPAAC)-mediated surface conjugation of disease-relevant peptides. We demonstrated that RBCs engineered by such approach retain their biophysical integrity and biocompatibility across a broad range of conjugation concentrations in vitro. Critically, when conjugated with single or multiple autoantigenic epitopes, these engineered RBCs elicited robust antigen-specific tolerance and drove durable disease remission in two well-established preclinical models, experimental autoimmune encephalomyelitis (EAE) and collagen-induced arthritis (CIA). Further mechanistic investigations revealed that the engineered RBCs reprogram antigen-presenting cells (APCs) toward a tolerogenic phenotype. This reprogramming, in turn, induces anergy in autoreactive T cells and suppresses the activation of autoreactive B cells. Collectively, this work establishes a versatile and clinically translatable platform, offering a path toward personalized, antigen-specific therapy for autoimmune diseases.