INDUCTION OF HOMOGRAFT TOLERANCE IN ADULT MICE BY SUBLETHAL X-IRRADIATION AND INJECTION OF HOMOLOGOUS SPLEEN CELLS

Abstract

1. Homograft tolerance was induced in adult DBA/2 mice by sublethal X-irradiation and an injection of a suspension of adult BALB/c spleen cells. 2. The optimal conditions for this procedure were determined by varying the dose of X-irradiation (200-400 r), the time of splenic injection (1 to 72 hours after irradiation), the time of skin grafting (1-17 days after irradiation), and the dose of spleen cells (0.01 to 1.0, expressed as a fraction to one spleen). The first 3 factors were found to be of maximal importance. 3. The mortality attributable to the entire procedure was 2%. 4. The procedure failed to induce tolerance across an H-2 barrier. 5. The possible use of this system as a model for studying tolerance induction and maintenance was emphasized.