title: The development of humoral immunological memory to a T-cell-dependent antigen requires thymic emigrant cells.
abstract: Immunological memory is embodied in the rapid and enhanced immune responsiveness to previously encountered antigens. Classically, memory would depend on the presence of small resting long-lived specific lymphocytes which, through clonal expansion after priming with antigen, would be present at higher frequencies than in naive animals. Here we report that T-cell-reconstituted athymic mice, which lack recent thymic emigrants, mount a primary response to a T-cell-dependent antigen, but do not develop memory or the capacity to produce specific anti-TNP IgG1 antibodies during the secondary immune response. On the other hand, if thymocytes are continuously provided during the secondary response, a typical secondary immune response is achieved with high levels of specific IgG1. These results lead us to propose that the development of humoral immunological memory cannot be explained solely by the long life span of primed T lymphocytes, but is rather a dynamic state dependent on the continuous presence of recent thymic emigrants and qualitative functional differences in responder T cells.
authors.affiliation: Department of Immunology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil.
authors.forename: D A
authors.initials: DA
authors.lastname: de Albuquerque
authors.forename: L S
authors.initials: LS
authors.lastname: Aroeira
authors.forename: O
authors.initials: O
authors.lastname: Williams
authors.forename: J
authors.initials: J
authors.lastname: Mengel
mesh_terms: D000818:Animals; D000941:Antigens / Q000276:immunology; D002465:Cell Movement / Q000276:immunology*; D002478:Cells, Cultured; D005260:Female; D016027:Heart Transplantation / Q000276:immunology; D007074:Immunoglobulin G / Q000096:biosynthesis; D007156:Immunologic Memory / Q000276:immunology*; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D013601:T-Lymphocytes / Q000276:immunology* / Q000637:transplantation; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*; D014301:Trinitrobenzenes / Q000276:immunology
chemical_list: D000941:Antigens; D007074:Immunoglobulin G; D007376:Interleukin-2; D014301:Trinitrobenzenes; D007371:Interferon-gamma