DC-CD4 bispecific tolerogenic nanovesicles induce antigen-specific regulatory T cells and ameliorate collagen-induced arthritis in mice

Inducing antigen-specific regulatory T (Treg) cells is a promising strategy for treating autoimmune diseases (AID). Here, we present dendritic cells-CD4⁺ T cells (DC-CD4) bispecific tolerogenic nanovesicles (NV) co-loaded with an antigenic peptide and rapamycin. We show that these NVs bring DCs and CD4⁺ T cells into close spatial proximity through CTLA4-CD80/86 and anti-CD4 (aCD4)-CD4 interactions, thereby promoting antigen-specific Treg cell generation. In a collagen-induced arthritis mouse model, the bispecific NVs display enhanced lymph node (LN) tropism and increase antigen-specific Treg cells in LNs and spleen, when administered in both therapeutic and prophylactic settings, resulting in robust efficacy against CIA. Furthermore, arthritogenic cell transfer and adoptive transfer of Treg cells into Treg-ablated mice confirm the pivotal role of bispecific NV-induced antigen-specific Treg cells in mediating the anti-inflammatory efficacy. Collectively, our data support DC-CD4 bispecific tolerogenic NVs as a platform to induce antigen-specific Treg cells for precise immune tolerance in AIDs. Strategies to induce a durable pool of antigen-specific regulatory T cells in vivo are of great interest for the treatment of autoimmune diseases. Here, the authors present a dendritic cell (DC)-CD4+ T cell bispecific nanoparticle-based platform that delivers collagen II peptide and rapamycin and show that the formulation facilitates the spatial coupling of DCs and CD4+ T cells, promotes a tolerogenic microenvironment and alleviates symptoms of rheumatoid arthritis in a preclinical mouse model.