Immunogenicity of allogeneic pancreatic islet grafts: the effect of in vitro culture and the site of transplantation

: Freshly isolated or cultured for 14 days rat allogeneic pancreatic islets were transplanted either intramuscularly or intratesticularly. After 14 days, the specific recipients' antigraft humoral and cellular immunity evaluated by means of leukoagglutination assay and indirect splenocyte migration inhibition test, respectively. Islet preculture resulted in significant decrease of humoral and in absence of cellular antigraft immunity irrespectively of site of transplantation. Intratesticular grafting did not evoke cellular response after transplantation of both fresh and cultured islets. However, antibody production after intratesticular transplantation of fresh islets remained unaffected. It may be concluded that preculture of rat pancreatic islets affects their immunogenicity. Moreover, testis appears to be a suitable immunoprivileged site for islet grafting.