title: Immune complex-mediated enhancement of secondary antibody responses.
abstract: Immunologic memory is a hallmark of the vertebrate immune system. The first antigenic exposure leads to a slow and modest immune response, whereas repeated exposure, even many years later, leads to a rapid and exaggerated response that is two to three orders of magnitude greater than the primary. In the case of humoral immunity, the increased efficacy of recall responses is due to the production of amplified levels of Ag-specific Ab, as well as the accelerated kinetics of their production. Current thinking suggests that this is due to selective activation of long-lived, Ag-specific memory B cells. A downside of restricting secondary responses solely to memory cells is that the repertoire of the memory B cell pool remains static while pathogens continue to evolve. In this study, we propose that during secondary responses, naive Ag-specific B cells participate alongside memory cells. We show that immune complexes formed in vivo between the Ag and pre-existing Abs from the primary response activate these naive B cells, inducing them to respond with accelerated kinetics and increased magnitude. Thus, the continued recruitment of new B cell clones after each antigenic exposure enables the immune system to stay abreast of rapidly changing pathogens.
authors.affiliation: Department of Microbiology and Immunology, Emory Vaccine Center, Yerkes National Primate Center, Emory University, Atlanta, GA 30329, USA.
authors.forename: Chelsey L
authors.initials: CL
authors.lastname: Goins
authors.forename: Craig P
authors.initials: CP
authors.lastname: Chappell
authors.forename: Rangaiah
authors.initials: R
authors.lastname: Shashidharamurthy
authors.forename: Periasamy
authors.initials: P
authors.lastname: Selvaraj
authors.forename: Joshy
authors.initials: J
authors.lastname: Jacob
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000906:Antibodies / Q000276:immunology; D000917:Antibody Formation / Q000276:immunology*; D000936:Antigen-Antibody Complex / Q000276:immunology*; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D003167:Complement Activation / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D056724:Immunity, Humoral; D007156:Immunologic Memory / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D017452:Receptors, IgG / Q000276:immunology
chemical_list: D000906:Antibodies; D000936:Antigen-Antibody Complex; D017452:Receptors, IgG