Carrier and hapten functions in immune deviation. II. Role of hapten and carrier on the helper functions of the T cells.

The kinetics of haemagglutinating and haemolytic antibody synthesis to the hapten and to the carrier determinants were studied in guinea-pigs injected intravenously with large doses of the carrier, or of the hapten conjugated to an homogous or heterologous protein carrier and subsquently immunized with the hapten-carrier conjugate in Freund's complete adjuvant. The animals treated with the heterologous conjugates exhibited enhanced reactions to the hapten and supressed reactions to the carrier, whereas the animals injected with the homologous conjugate showed depressed reactions to the hapten but unaffected reactions to the carrier. Pretreatment with the carrier alone-seemed to have no effect. These experiments confirm that the hapten determinant must act at the T-cell level but do not exclude the possibility that it could also act at the B-cell level. On the other hand, they allow the dissociation of the different components of the immune response directed against the hapten and carrier determinants of the antigen molecule in immune deviation.