The Induction of Delayed Hypersensitivity by Macrophage-associated Antigen.

The regulation of the immune responses by antibody administered passively on peritoneal exudate cells (PEG) was studied in guinea-pigs. The immunogenicity of sheep red blood cells (SRBC) associated with PEC for the induction of delayed hypersensitivity (DH) to soluble erythrocyte antigen was enhanced when PEG were incubated with anti-SRBG antibody. In contrast, the antibody response to SRBC was depressed. This phenomenon was only observed with specific antibody and was partially blocked when PEG covered with anti- SRBC antibody were incubated with rabbit anti-guinea-pig globulin serum. Comparable amounts of anti-SRBC antibody injected separately had no enhancing effect. Anti-SRBC sera from which the cytophilic antibody activity had been removed were inactive. PEG-associated SRBC were usually more immunogenic than the same amount of `free' SRBC for the induction of delayed hypersensitivity and always more immunogenic for antibody production. These observations suggested that macrophage cytophilic antibody might be involved in the regulation of the immune response and play a role in the preferential induction of delayed hypersensitivity in the studied system. [ABSTRACT FROM AUTHOR]