The Relation of Antigen and Virus Localization to the Development and Growth of Lymphoid Germinal Centers

Abstract

Early morphologic studies emphasized the proliferative capacity of secondary lymphoid follicles: this resulted in the acceptance of the term “germinal center” as a distinct component of the primary lymphoid follicle. These centers were also characterized by extensive cell death, and it was apparent that both of these phases of the secondary follicle were prominent during an immune or foreign- body reaction. “Dissociation” (a loss of the germinal centers) was a further aspect described by Congdon and Makinodan [1] and later elaborated by Hanna [2]. This response occurred in spleen lymphoid follicles during the first 48 hr after intravenous injection of supra-optimum antigen doses. Loss of the germinal centers was attributed to a dissociative growth of their characteristic large pyroninophilic lymphoid cells into the primary follicle and spleen red pulp. The occurrence of dissociation during the induction phase of the primary immune response suggested that the lymphoid cells of the germinal centers might be precursors of the specific antibody-producing cells. This dissociation was succeeded by hyperplasia of the secondary follicle. As shown in antigen dose studies the hyperplasia was present at all antigen doses, whereas the dissociation was only achieved at optimum and supra-optimum doses [3, 4].