IMMUNITY AND IMMUNOTOLERANCE TO BOVINE HEART ANTIGENS IN THE RAT.

Rats, injected with crude bovine heart extracts, showed dissociation of their immunological response. Complement-fixing and capillary precipitating antibodies were produced, active against particulate antigens, while tanned-cell haemagglutinating and gel-diffusing antibodies were active against soluble antigens. Particulate antigens were centrifuged down from tissue extracts at 60,000 but not at 12,000 . The kinetics of production and specificity differed in the two groups of antibody. When rats were injected with bovine tissues from birth, to produce immuno-tolerance, they did not produce complement-fixing or capillary precipitating antibodies on later challenge with bovine heart but did produce haemagglutinating and gel-diffusing antibodies. Even before challenge, pretreated rats showed haemagglutinating antibodies, while the response by this test to the further immunization was partially suppressed.