Abstract
Transfer of thymus cells from young chickens to syngeneic recipients suppresses the allograft rejection between strains differing at the major histocompatibility (B) locus. Thymus cell transfer in combination with a light whole body irradiation (360 R) prolongs significantly the mean rejection time of skin allografts and leads in a proportion of recipients to long-lasting graft survival (greater than 200 days). Three weeks after the cell transfer, the suppression appears to be antigen specific, as judged by the normal reactivity against third-party skin grafts. From the types of thymus cells preparations that are effective in these experiments, it is inferred that the suppressor cell is a bursa-dependent lymphocyte, which is predominantly found in the young chicken thymus and which is different from B-lymphocytes, B-precursor cells, or graft-versus-host-reactive T-cells.