[The influence of pretreatment with specific antibodies on Renal Xenograft Rejection (author's transl)].

26 pig kidneys were perfused in a "Gambro" kidney perfusion machine. The perfusates used were unmodified canine plasma and serum, as well as complement-free plasma, gamma-globulin solutions obtained from dogs immunized against pig leucocytes (ALG) and 2-mercapto-ethanol treated ALG (2 ME-ALG). The typical pig-to-dog xenograft rejection was reproduced by ex vivo perfusion with native dog plasma and serum. Using complement-free dog plasma, ALG and 2 ME-ALG pig kidneys could be perfused for several hours without significant increase in perfusion resistance. 22 pig kidneys, pretreated by perfusion for 2 hours with complement-free dog plasma, ALG and 2 ME-ALG, were transplanted on to the vessels of the neck of recipient dogs. Grafts pretreated with decomplemented dog plasma and 2 ME-ALG were rejected in the usual fashion within 5 to 20 min. Pretreatment with ALG resulted in a prolongation of graft function for 80 to 100 min. It is suggested that ALG exerted a transient blocking effect on the cytotoxic action of recipient IgM resembling passive enhancement; this phenomenon may be limited to sites with low antigen density, corresponding to in vitro findings of passive enhancement on cells with low surface antigen density.