γ-Globulin and Antibody Formation in Vitro

Abstract

Summary Separated white and red pulp of the spleen obtained from rabbits at various days after an intravenous injection of sheep erythrocytes (SE) were examined for numbers of plaque-forming cells (PFC) on SE-containing agar. It could be shown that both white and red pulp contained many antibody-forming cells on days 4 to 5, but that only the white pulp had the ability to develop PFC in vitro if taken on day 2 and kept in vitro for another 2 days. With tissue taken on days 2 to 42 after a primary injection of SE, reexposure to SE in vitro and subsequent culturing for 4 to 5 days resulted in an increase in the numbers of PFC above initial levels. The white pulp usually contained a greater proportion of “sensitized” cells than the red, especially when kept in vitro for 1 day before the reexposure to antigen. Some white pulp preparations taken on days 4 to 12 reacted better when reexposed on day 1 than on day 0 of the culture period. Since this time period corresponds to the time of secondary nodule proliferation, the results are interpreted as indicating formation of “sensitized” cells in secondary nodules.