The role of thymus-derived lymphocytes in an antibody-mediated hapten-specific helper effect.

The cellular basis of the antibody-mediated, hapten-specific anti-idiotype antibody response of CBA/J mice to a hapten conjugate of the BALB/c myeloma protein LPC-1 was examined. Previous studies have shown that anti-idiotype antibody is produced if the mice are given anti-2,4-dinitrophenyl (DNP) antibody and then immunized with DNP-LPC-1; immunization with DNP-LPC-1 or LPC-1 alone does not lead to the production of this antibody. In the present experiments, mice depleted of thymus-derived lymphocytes by two different techniques failed to make anti-idiotype antibody after transfer of anti-DNP antibody and immunization with DNP-LPC-1. However, thymus-deprived mice given anti-DNP antibody and reconstituted with thymus-derived spleen cells did make anti-idiotype antibody in response to DNP-LPC-1. Thymocytes could not reconstitute such mice for this response. The possible mechanisms for this hapten-specific, antibody-mediated, T cell-dependent helper effect are discussed. It is felt that such helper effects represent an alternate pathway to conventional specific T cell-mediated cooperation. Further examples of antibody-mediated helper effects which support this hypothesis are also presented.