Double immunocytochemical evidence for a clonal development of specific antibody-containing cells in the rabbit spleen.

Rabbits were intravenously primed with the antigens human serum albumin (HSA) and bovine gamma globulin (BGG). The antigens were given simultaneously, or at an interval of 1, 2, or 4 days. After 2 months an intravenous booster injection with both antigens was given simultaneously. The localization pattern of anti-HSA-antibody-containing cells and of anti-BGG-antibody-containing cells in the spleen was determined during both the primary and secondary immune response. Anti-HSA-antibody-containing cells and anti-BGG-antibody-containing cells were not distributed randomly but, rather, were found in defined groups during the induction of an immune response. The most probable explanation for this grouping is that lymphoid cells, once triggered to proliferation by a particular antigen, show a clonal development in the spleen. During their proliferation and successive antibody formation, they migrate only slowly, so that they remain close together. Specific-antibody-containing cells were also detected in the popliteal lymph nodes and in the appendix of the rabbits.