Inhibition of delayed hypersensitivity by pre-immunization without complete adjuvant

Abstract

Guinea-pigs were immunized by injections of blood group substance with incomplete adjuvant, followed after an interval of approximately 2 weeks, by intracutaneous immunization with the same antigen and Freund's adjuvant containing M. tuberculosis. This treatment inhibited the appearance of delayed skin reactions, while circulating antibody production took place as in controls which had received complete adjuvant only with blood group substance, and had delayed skin reactions. The inhibition of the skin reaction was found to be antigen-specific with regard to unrelated antigens, but showed cross-inhibition for serologically different human blood group substances. The first immunization had to be given more than 2 days before the immunization with complete adjuvant. A similar phenomenon was seen with ovalbumin as antigen. In addition to inhibition of the delayed skin reaction, there appeared to be less γ₂-antibody to ovalbumin than in ovalbumin plus complete adjuvant-only controls. Passive administration of antibody did not affect the development of a delayed hypersensitivity state in complete adjuvant-immunized animals with blood group substance or ovalbumin as antigen. Present evidence favours an explanation of the phenomenon in terms of temporary paralysis on the part of some of the antibody-producing cells—viz. those concerned with delayed hypersensitivity and γ₂-antibody production.