The effect of the carrier protein on the immune response and on the induction of tolerance in mice to the 2,4-dinitrophenyl determinant.

The role of the protein carrier on the primary and anamnestic response to the 2,4-dinitrophenyl (DNP) determinant was studied in randombred ICR and in an inbred BALB/c AnNIcr strain of mice. It was found that the level of the response was related to the immunogenicity of the carrier molecule. Mouse γ-globulin (MGG) was the most effective carrier for inducing tolerance to DNP regardless of the route of administration, while only occasional tolerance was achieved with the highly immunogenic haemocyanin. When human γ-globulin (HGG) served as a carrier, hyporesponsiveness to the DNP group was induced in the majority of neonate and adult mice when injected intraperitoneally, while an immune response ensued when the antigen was incorporated in adjuvant and injected into the footpads. Conversely, the most effective carrier for immunization against the DNP determinant was haemocyanin, while little immunity against either DNP or the protein carrier resulted from immunization with DNP—MGG. The antibody response of the mice when measured by the passive tanned haemagglutinating test was directed mostly against the hapten carrier complex and the protein carrier rather than the DNP-determinant alone, regardless of the initial route of administration. In contrast to the results obtained in vitro, the antibody responsible for the PCA reaction in mice is directed exclusively against the hapten and the hapten—protein conjugate but not against the protein carrier.