Abstract
The effects of immunization with the terpolymer of L‐glutamic acid60‐L‐alanine40‐L‐tyrosine10 (GAT), the copolymers of L‐glutamic acid60‐L‐alanine40 (GA) and of L‐glutamic acid50‐L‐tyrosine50 (GT), were compared in adult and newborn BALB/c and BALB.B mice. As expected, BALB/c (H‐2d) and BALB.B (H‐2b) adult mice were responders to GAT and GA and nonresponders to GT, which induced suppressor T cells in BALB/c but not in BALB.B mice. In contrast, newborn mice expressed different phenotypes. Two‐week‐old mice developed responses to GAT, GA and GT‐complexed methylated bovine serum albumin, but immunization at birth with these copolymers induced a cross‐reactive tolerance in both strains. Neonatal GAT tolerance could be transferred in adult and involved suppressor T cells in the two inbred strains, whereas the GT‐specific immune suppression was not demonstrable in newborn BALB/c mice. The significance of these data to our understanding of the regulation of specific immune response and tolerance is discussed.