Rabbits immunized with bovine serum albumin were irradiated during the primary and secondary responses, and antibody production after subsequent antigenic injections was studied. Antibody levels were measured by the ammonium sulfate precipitation method of Farr.
Irradiation during the steady state of the primary response produced a continuous fall in antibody levels, but was without effect when given during the declining antibody phase of the secondary response. In either case, the antibody response to a subsequent antigenic injection was greatly inhibited.
Irradiation did not alter the change in antibody avidity occurring during the primary and secondary responses.
These results are discussed in the light of current theories of cell population dynamics in the antibody response.