Detection of Immune Response Against Synthetic Polymers of Amino Acids Employing the Plaque-Forming Cell System

Abstract

Lymph node tissue from rabbits sensitized with the synthetic terpolymer, G₄₂L₂₈A₃₀, was found to contain antibody-forming cells capable of reacting with GLA-coated erythrocytes in the agar plate method originally devised by Jerne and Nordin. Sheep anti-rabbit globulin completely inhibited the anti-GLA activity in the plaque-forming cells obtained during the early stages following both primary and secondary immunization. Soluble GLA₃₀ (2.4 mg) incorporated into the upper layer also inhibited the response; in contrast, lower concentrations of GLA₃₀ (0.02 mg) had no effect. Passive hemagglutination titers of the sera against GLA-coated sheep cells indicated no correlation between these titers and the magnitude of the plaque-forming cell response in the lymph node tissue, with the possible exception of sera obtained in the early phases following primary immunization. Differences in the reactions against untreated sheep cells and the GLA-coated cells were discussed, including the appearance of the hemolytic zones and the effect of sheep anti-rabbit globulin sera.