Plasma Cellular Reaction and its Relation to the Formation of Antibodies in vitro

Abstract

DURING secondary response, elicited in sensitized rabbits by means of intravenous injections of the homologous antigen, the number of plasma cells in the spleen increased considerably, simultaneously with the formation of antibodies¹. The cellular reaction was localized almost exclusively to the red pulp, especially after the injection of living Salmonella typhi (about 500 millions/kgm.). The spleen was investigated by means of biopsies at intervals during antibody formation ; differential counts of imprints were made and histological sections were examined. The stain used was methyl green pyronine (Unna–Pappenheim). In the earliest stages of the reaction, in the first phase of antibody formation, large reticulum cells of characteristic appearance (called transitional cells) presented themselves. One or two days later, immature plasma cells appeared at the places where transitional cells were previously found, and after a further few days mature plasma cells were seen in increasing noimbers. There were numerous transitions between the different stages of development. No plasma cells were usually seen in the lymph follicles.