Intracellular distribution of antibodies in rat lymph node cells during primary response. A kinetic study.

The kinetics of appearance of immunoglobulin- and antibody-containing cells in rat lymph nodes was studied by immunoenzymatic techniques between days 12 and 90 after a single injection of horse-radish peroxidase. Three distinct phases appeared during the primary repsonse. Between days 8 and 17, essentially no antibody-containing cells were detectable, while non-specific immunoglobulin-containing cells amounted to up to 9% of the total cell population. The peak of antibody-forming cells was observed between days 18 and 24, and their number decreased slowly during the last phase. Days 18-20 were marked by a sharp peak of a distinct category of cells containing antibodies in a limited area of their cytoplasm. One day before this event, the percentage of immunoglobulin-forming cells decreased drastically, and remained very low throughout the response. These results are discussed on the basis of a previously published model, which proposes that non-specific immunoglobulin-containing cells are precursors to antibody-containing cells, and that the transformation between these two categories of cells involves a stage where antibody synthesis is restricted to a few endoplasmic reticulum vesicles.