The immunogenicity of three random copolymers of amino acids with L-glutamic acid and L-alanine (GA), L-glutamic acid and L-tyrosine (GT), or L-glutamic acid, L-alanine, and L-tyrosine (GAT), administered in complete Freund's adjuvant, was studied in several inbred and random-bred guinea pig strains. The animals were tested for delayed sensitivity and their sera were assayed for the presence of antibody directed against the immunizing polymer. All of the guinea pigs developing delayed hypersensitivity also had significant antibody levels in their sera.
Inbred strain 2 guinea pigs responded to immunization with GA, but failed to form detectable responses to GT. Inbred strain 13 animals, on the other hand, responded to GT, but not to GA. The (2 x 13)F1 hybrids responded to both GA and GT with both delayed hypersensitivity and circulating antibody. Thus, the ability of these inbred guinea pigs to respond immunologically to GA or GT is controlled by distinct autosomal dominant genes.
A variable percentage of random-bred guinea pigs, depending on their source as well as their strain, responded to immunization with GA and with GT.
All guinea pigs, both inbred and random bred, responded to immunization with GAT. The ability to respond immunologically to GAT, therefore, does not seem to be under simple genetic control. However, the levels of anti-GAT antibody found in the sera of animals lacking the ability to respond to GA were much lower than those detected in GA responder animals.