Anti-CD3 microporous annealed particle hydrogel protects stem cell derived beta cells from autoreactive T cells

Abstract Type 1 diabetes (T1D) results from autoimmune destruction of pancreatic beta cells, leaving patients dependent on exogenous insulin and at risk of severe hypoglycemic episodes. Stem cell-derived beta-like cells (sBCs) offer a promising approach for beta cell replacement therapy, but clinical translation is limited by immune-mediated rejection, recurrent autoimmunity, and inhospitable transplantation sites. Biomaterials have been investigated to provide localized immune-isolation and immunomodulation, but foreign body responses and rapid depletion of therapeutic agents remain as obstacles to clinical translation. Here, we present a microporous annealed particle (MAP) hydrogel functionalized with an anti-CD3 monoclonal antibody (αCD3) to provide a localized immunomodulatory microenvironment for beta cell replacement therapy. MAP hydrogels consisting of guest-host interlinked polyethylene glycol-maleimide (PEG-MAL) microgels supported rapid vascularization, minimal foreign body response, and engraftment of syngeneic islets in mice. αCD3 MAP hydrogel halted T cell migration in vitro and protected transplanted sBCs from immune-mediated destruction by HLA-matched diabetogenic T cells in vivo. Subcutaneous αCD3 functionalized MAP hydrogel also protected the endogenous islets in the pancreas, demonstrating potential for systemic immune modulation. These findings establish αCD3 MAP hydrogels as a promising strategy for localized immune modulation in cell replacement therapy. Competing Interest Statement AEW, CTM, JMB, HAR, and EAP have submitted a patent application (Anti-CD3 Granular Hydrogel for Immune Protection of Cell Therapies, PCT/US2025/046595) on αCD3 MAP, assigned to the University of Florida. HAR is the scientific cofounder of Tolerance Bio and consults for Tolerance Bio, Guidepoint Global, Axxon Advisors, and Sernova Biotherapeutics. JMB consults for Tolerance Bio. Footnotes adriennejan25{at}ufl.edu (AEW) cameronmanson{at}ufl.edu (CTM) jessiebarra{at}ufl.edu (JMB) Cp.spencer{at}ufl.edu (CPS) agrodman{at}ufl.edu (ADG) macmillanladd.a{at}ufl.edu (AML) holger.russ{at}ufl.edu (HAR) ephelps{at}bme.ufl.edu (EAP) Data Availability Statement The datasets generated and/or analyzed during the current study are available from the corresponding author on request. Funding Statement The studies presented here were supported by Breakthrough T1D (JDRF SRA-2019-781-S-B) and NIH grants NIDDK R01-DK132387 and NIDDK R01-DK124267. JMB was supported by the Advanced Postdoctoral Fellowship 3-APF-2024-1492-A-N by BT1D and the Thomas H. Maren Research Excellence Postdoctoral Award by UF. Conflict of Interest Disclosure The authors have submitted a patent application (Anti-CD3 Granular Hydrogel for Immune Protection of Cell Therapies, PCT/US2025/046595) on αCD3 MAP, assigned to the University of Florida. HAR is the scientific cofounder of Tolerance Bio and consults for Tolerance Bio, Guidepoint Global, Axxon Advisors, and Sernova Biotherapeutics. JMB consults for Tolerance Bio. Ethics Approval Statement All experiments involving animals were approved by the University of Florida Animal Care and Use Committee (IACUC no. 202200000503).