title: Hepatitis B surface antigen-specific T and B cell memory in individuals who had lost protective antibodies after hepatitis B vaccination.
abstract: Long-term protection after hepatitis B vaccination is dependent on the persistence of a strong immunologic memory. In search of reliable markers for a hepatitis B surface antigen (HBsAg)-specific immunological memory we studied the cellular and humoral immune responses of 15 healthy individuals who were successfully vaccinated but had lost anti-HBs titers. To determine the reactivity of vaccine-induced HBsAg-specific T cells of both effector and memory phenotype CD4+/CD45RA+ and CD4+/CD45R0+ T cells, respectively, were isolated, stimulated with HBsAg and tested for IFN-gamma and IL-5-secretion by enzyme-linked immunospot assays (Elispot). To detect even small numbers of specific T cells, we enriched the appropriate subpopulation from the entire PBMC population. B cell memory was analysed by cocultivation of isolated B cells with CD4+ T cells and identification of anti-HBs-secreting cells by Elispot. All individuals were revaccinated and humoral and cellular responses were determined. The results showed significant numbers of HBsAg-specific memory T and B cells present in all vaccinees despite the absence of specific antibodies. Our data suggest that individuals who had lost their anti-HBs seropositivity still show immunologic T cell memory and that these T cells are able to trigger anti-HBs production of B cells activated by revaccination.
authors.affiliation: Institute for Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany. tanja.bauer@klinik.uni-regensburg.de
authors.forename: Tanja
authors.initials: T
authors.lastname: Bauer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Jilg
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D015415:Biomarkers; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000378:metabolism; D005260:Female; D006509:Hepatitis B / Q000276:immunology*; D006510:Hepatitis B Antibodies / Q000032:analysis*; D006514:Hepatitis B Surface Antigens / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology*; D007371:Interferon-gamma / Q000097:blood; D015848:Interleukin-5 / Q000097:blood; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D014611:Vaccination
chemical_list: D015415:Biomarkers; D016207:Cytokines; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D015848:Interleukin-5; D007371:Interferon-gamma