Antibody Production by Isolated Spleen Cells: A Study of the Cluster and the Plaque Techniques

In previous publications, cluster formation as an expression of antibody production by isolated spleen cells has been described and compared with the results of the plaque technique. In the present study these investigations have been extended and the conclusion is drawn that cells producing IgM antibodies can form both clusters and plaques. The cells producing IgG antibodies readily form clusters, whereas plaque formation only occurs when anti-mouse-γ-globulin is added (indirect plaque formation). Evidence is presented that cluster formation does not always depend on the excretion of antibodies. At 4 days after immunization about 40% of the clusters were formed by cells which did not excrete antibodies during in vitro incubation. Within the remaining 60% of cluster-forming cells a large variation in the amount of excreted antibodies was found. The function of the inactive cells is still uncertain. In view of their persistence long after the primary response, some of them may be “memory” cells responsible for the anamnestic response. Investigation of this subject is in progress.