Reaginic Antibody Formation in the Mouse

Abstract

Abstract DBA/1 mice were immunized with various doses of dinitrophenyl-ovalbumin (DNP-OA) precipitated with aluminum hydroxide gel, and both the reaginic (IgE) and IgG antibody responses were observed. Mice immunized with a minimal dose of DNP-OA, i.e., 0.02 to 0.05 µg, showed a persistent formation of anti-DNP IgE antibody, while an increase of immunizing dose resulted in only a transitory response. Formation of anti-OA IgE antibodies was persistent when animals were immunized with 0.02 to 1 µg of DNP-OA. Anti-DNP IgG antibody appeared in the serum within 10 days after immunization and reached a maximum by 2 weeks, whereas the anti-OA antibody titer increased slowly. The concentration of anti-DNP IgG antibody was much higher than anti-OA antibody during the first 3 weeks. The results showed that an optimal dose of immunizing antigen for maximal response differed with the immunoglobulin class of antibodies and antigenic determinant, even though the determinants are present on the same antigen molecule. Priming of mice with suboptimal doses, i.e., 0.02 µg to 0.05 µg, of OA for antibody formation 2 weeks before immunization with DNP-OA either enhanced or “accelerated” both IgE and IgG anti-hapten and anti-carrier antibody responses. The results indicated participation of carrier-specific helper cells in the formation of anti-hapten IgE antibody. When animals were primed with 1 to 10 µg of OA, which was sufficient for induction of both IgG and IgE antibody response, and then immunized with DNP-OA, formation of anti-hapten antibodies was suppressed. The immunization of the primed animals with the hapten-carrier conjugate resulted in secondary response of both IgE and IgG anti-carrier antibodies.