EXPLANATION: This hypothesis is described in detail in the review article (SEE REF) along with the experimental evidence leading to its development. Since 1980, new data was developed. For example the new observations on antigen transport and on the maturation of FDCs [i.e., from the filiform (yarn or string) type dendrites to the beaded dendrites), and the discovery of ICCOSOMEs. These have been since incorporated into the alternative antigen transport pathway along with the observation of the formation of the "ball of yarn" configuration of filiform FDC dendrites at the end of two weeks after antigen injection into immune mice.
FIGURE 1. A model for feedback regulation of antibody synthesis during the maintenance phase of the immune response. The injection of antigen and the subsequent induction of the primary immune response results in the production of specific antibody, the generation of a population of primed lymphocytes, and a population of follicular dendritic cells with surface associated persisting antigen. Later in the maintenance phase of the immune response, multiple dynamic equilibria are postulated to exist between persisting antigen, free specific antibody, and antigen- antibody complexes of various ratios in the lymphoid organs. The immunogenicity of the complexes is directly related to the antigen-antibody ratio and alterations in serum antibody levels result in formation or dissociation of these complexes. When antibody levels in the circulation decline, antigenic determinants are exposed, memory B- cells are stimulated, and a new cycle of antibody synthesis is induced. This newly produced antibody feeds back and terminates the immunogenic stimulus. Repetition of this cycle serves to maintain serum antibody levels within narrow limits for long periods of time. -- For further detailes of this review see: The Maintenance and Regulation of the Humoral Immune Response:Persisting antigen and the Role of Follicular Antigen-Binding Dendritic Cells. By Tew, Phipps and Mandel, Immunol.Rev. 1980, Vol. 53, pp. 175-201. SEE REF.