Immunological unresponsiveness in guinea pigs. I. Immunological unresponsiveness to heterologous serum proteins.

A state of immunological unresponsiveness to bovine serum albumin (BSA) or human gamma globulin (HGG) can be produced in guinea pigs by contact with these proteins either before and soon after birth, or even soon after birth alone. As judged by failure of treated animals to show immune elimination of the antigen, or anaphylaxis on reinjection, the animals were completely unresponsive when tested up to 5 months after birth. Administration of 6-mercaptopurine to guinea pigs, even in lethal doses, did not prevent the development of antibodies to HGG. After administration of BSA or HGG, labelled with 131I, to pregnant guinea pigs, their offspring at term contained significant amounts of the labelled proteins. HGG was catabolized in new-born guinea pigs with the same half-life as in adults.