The relationship between lymphocyte transformation and immune response. 3. Kinetics of production of antibody forming cells and transforming cells.

Rabbits immunized with a single dose of sheep erythrocytes were used to compare the kinetics of production of antibody forming cells (both rosette and plaque forming cells) and lymphocytes that transform in culture in the presence of the specific antigen. The latter activity is assumed to represent immunological memory. Low levels of the three cellular activities were detected in most unimmunized animals. The first response to be found in the immunized animals was an increase in number of PFC in the spleen, 3 days after injection, while rosette forming and transforming cells increased a day or two later. Active cells were detected in the blood of most animals about 1 day after they were found in the spleen. High levels of all activities were present 5–17 days after immunization. Spleen cells from rabbits tested 84–360 days after immunization showed remarkable levels of transformation activity, while the values of plaque and rosette-forming cells fell as low as in unimmunized (`background' levels). On the other hand, blood lymphocytes exhibited almost no transformation or antibody formation activity. Lymph node cells, tested in a few rabbits, exhibited intermediate degrees of transformation response.