Brief Report: Immune Response in Mice with Plasma-Cell Tumor (X5563) Assayed by Agar Plaque Technique

The immune response to sheep erythrocytes in mice with the gamma-type plasma-cell tumor (X5563) was measured on a cellular level by agar plaque technique of Jerne et al. It was demonstrated that there was a reduction in the number of plaque-forming cells involved in the primary response but not in the secondary response in the mice which were immunized shortly before the inoculation of the tumor. These findings indicate that the lowered antibody response in mice with the tumor is due to a diminished number of antibody-forming cells.