Immune competence of the streptozotocin-induced diabetic rat. I. Absent second-set skin allograft response

A study was designed to assess the cellular immune competence of Lewis rats with streptozotocin-induced diabetes. First-set Fischer skin allografts were rejected in 10.9 days by nondiabetic Lewis recipients and in 12.0 days by diabetic Lewis recipients. Second-set skin allografts in the same strain combination, utilizing the same recipients, were rejected in 8.1 days by nondiabetic recipients and in 13.0 days by diabetic recipients (P less than 0.01), indicating an absence of second-set rejection in the streptozotocin-induced diabetic rat. Treatment with NPH insulin, 3 units daily, although only slightly corrective of hyperglycemia, reduced second-set graft rejection to 8.0 days. These findings offer evidence of impaired cellular immune responsiveness in the streptozotocin-induced diabetic rat. Insulin was shown to correct deficient allograft immunity.