This study tests a three-phase immune treatment for people recently diagnosed with Type 1 diabetes (within 6 months, with some insulin production remaining).
Phase 1 (weeks 1-2): Teplizumab, an anti-CD3 antibody, is given by infusion to slow immune attack on insulin-producing beta cells.
Phase 2 (months 2-9): Insulin is injected directly into a lymph node (intralymphatic immunotherapy, ILIT) alongside low-dose interleukin-2 to teach the immune system to tolerate insulin and expand protective regulatory T cells.
Phase 3 (months 10-24): Low-dose interleukin-2 is continued to maintain immune tolerance.
The main goal is to preserve the body's remaining insulin production (measured by C-peptide). Sixty adults aged 18-45 will be randomly assigned to the MATIN-2 protocol or standard care. Safety, immune markers, and HbA1c will also be monitored.