Antibody production in mice. 3. The suppressive effect of antibody on the initiation of secondary immune response.

The suppressive effect of antibody on the secondary immune response was analysed using a technique of memory cell transfer into X-irradiated recipients. The response of memory cells stimulated by antigen-bearing cells was markedly suppressed when antibody was passively administered to recipients and this had its maximal effect when administered simultaneously with the cell transfer. The capacity of memory cells to respond to antigenic stimulation and the capacity of antigen-bearing cells to stimulate memory cells were not directly impaired by the suppressive antibody. The marked suppression was observed only when both memory cells and antigen-bearing cells were present together with antibody. These results suggest that antibody-induced suppression appears to be caused by blocking the effective antigenic stimulus from antigen-bearing cells to memory cells. Evidence is presented indicating that pre-existing antibody plays a regulatory role in the initiation of the secondary response and also controls the expression of memory.