THE LOSS OF PARTIAL TOLERANCE FOLLOWING SUB-LETHAL IRRADIATION

Abstract

Rats injected neo-natally for eight weeks with sheep erythrocytes showed partial or complete tolerance (suppression) when immunized at 13 weeks of age. The degree of suppression was greater for saline than for incomplete agglutinins. Sub-lethal irradiation of the tolerant rats caused a loss of tolerance as measured by the levels of circulating saline agglutinins, incomplete agglutinins and hemolysins against sheep erythrocytes. There was a definite tendency to lose tolerance spontaneously among the tolerant non-irradiated rats when antibodies were measured as hemolysins, but not when antibodies were measured as saline or incomplete agglutinins. These data are compatible with the hypothesis that the persistence of antigen is necessary for the maintenance of tolerance.