[Active enhancement of rat kidney grafts by immunization of the recipients with donor-specific nylon-adherent spleen lymphocytes].

At different intervals (2, 4, 8, 12 and 21 days) after preimmunization of BD IX inbred rats with density gradient-separated nylon-wool-adherent spleen lymphocytes from rats of the MHC different inbred strain Sprague-Dawley, (BD IX X SD)F1 kidneys were transplanted into the immunized BD IX rats. The non-immunized control rats died after 11-16 days. Kidneys transplanted 8 or 12 days after preimmunization survived indefinitely without any signs of rejection. In contrast, the rats grafted 2 and 4 days after preimmunization showed elevated levels of blood urea nitrogen (mean: 70-83 mmol/l) on the 7th post-operative day. The transplantation on day 21 resulted in a slight rejection episode on the 7th postoperative day. These results suggest the efficacy of nylon-wool-adherent lymphocytes in inducing an active transplant protection.