An anti-CD103 antibody-drug conjugate prolongs the survival of pancreatic islet allografts in mice

CD103 mediates T-cell infiltration and organ allograft rejection, and depletion of CD103-expressing cells is a promising therapeutic strategy for allograft intolerance. Recently, we verified that M290-MC-MMAF, an anti-CD103 antibody-drug conjugate, potently eliminates CD103-positive cells in vivo, with high specificity and minimal toxicity. However, the contribution of M290-MC-MMAF to blocking the CD103/E-cadherin pathway involved in transplant rejection remains unclear. Herein, we examined the impact of systemic administration of M290-MC-MMAF on allografts in an islet transplantation model. M290-MC-MMAF treatment maintained the long-term survival of islet allografts (>60 days) compared to mock injection or unconjugated M290 antibody treatment (<18 days). The change was associated with a decrease in CD103⁺CD8⁺ effector T cells and an increase in CD4⁺CD25⁺ regulatory T cells. CD103⁺CD8⁺ effector T-cell transfer or CD4⁺CD25⁺ regulatory T-cell depletion resulted in a rapid loss of allografts in long-surviving islet hosts. Moreover, M290-MC-MMAF treatment reduced IL-4, IL-6, and TNF-α expression levels and increased IL-10 expression in the grafts, which presented an immunosuppressive cytokine profile. In conclusion, targeting CD103 with M290-MC-MMAF induced immunosuppression and prolonged the survival of pancreatic islet allografts in mice, indicating the potential clinical value of M290-MC-MMAF in therapeutic interventions for allograft rejection.