The Morphologic Demonstration of Antibody Formation in Follicles of Lymphoid Tissue

Abstract

The important role of lymphoid follicles and associated germinal centers in immune processes has been inferred from evidence obtained over many years by histologic observations (Fitch and Wissler, 1965; Ehrich, 1965). There is, however, only scant knowledge as to the actual biologic function of these structures. Increasingly convincing evidence of the relationship of lymphoid structures to antibody formation has been obtained during recent years, but the methods which have yielded most of the available information have been, in the main, indirect. Thus, sequential histologic changes in spleens of immunized animals have been described and correlated with appearance of specific antibody in the circulation (Congdon and Makinodan, 1961; Hanna, 1964, 1965). It is assumed that changes observed in the lymphoid organs are related to the formation of the antibody being studied. More recently, the use of fluorescent labeled antibodies has yielded evidence of follicular antibody localization, but generally only in connection with the secondary response (Coons, 1958; Ortega and Mellors, 1957; White, 1963). Radioautographic studies have demonstrated increased metabolic activity in lymphoid follicles and germinal centers after specific immunization (Fliedner, et al., 1964; Swartzendruber and Hanna, 1965), as well as apparent localization of injected radio-labeled antigen to follicles (Nossal, 1962, 1965; Sweet et al., 1965).