Prolonged Survival of Skin Homografts in Adult Mice following Sub-lethal Irradiation, Injection of Donor-Strain Spleen Cells and Administration of A -Methopterin

IT has been reported previously from this laboratory 1 that a high proportion of adult A -strain mice exposed to 500 r. whole-body irradiation followed by the injection (divided between the intra-peritoneal and intravenous routes) of 800 million–1,200 million ( CBA × A ) F 1 hybrid spleen cells, become specifically tolerant of homografts of ( CBA × A ) F 1 skin. On the other hand, four of five A -strain mice which received 500 r. whole-body irradiation and 700–800 million CBA spleen cells died after intervals ranging from 6 to 25 days with clinical and pathological signs of graft-versus-host disease, and the solitary survivor showed no tolerance to CBA skin.