Adverse events will be monitored and recorded throughout the first year post-transplant. The proportion of surgical and type 1 diabetic subjects receiving an islet allotransplant who achieve and maintain full or partial islet graft function during the first year post-transplant will be determined to assess the efficacy of hOKT3gamma1 (Ala-ala) administration. Successful completion of the proposed clinical trial will increase our understanding of the safety, efficacy and underlying mechanisms of selective immunotherapy with the anti-CD3 monoclonal antibody hOKT3gamma1 (Ala-ala) for the maximization of engraftment and functional survival of allogeneic human islets in surgical and type 1 diabetic recipients.