title: Persistence and responsiveness of immunologic memory in the absence of secondary lymphoid organs.
abstract: Secondary lymphoid organs (SLOs) promote primary immune responses by recruiting naive lymphocytes and activated APCs. However, their role in the persistence or responsiveness of memory lymphocytes is unclear. We tested whether memory cells were maintained and could respond to challenge in the absence of SLOs. We found that influenza-specific CD8 cells in the lung acquired a memory phenotype, underwent homeostatic proliferation, recirculated through nonlymphoid tissues, and responded to and cleared a challenge infection in the complete absence of SLOs. Similarly, influenza-specific virus-neutralizing antibody was generated and maintained in the absence of SLOs. Inducible bronchus-associated lymphoid tissue (iBALT) was also formed in the lungs of previously infected mice and may provide a niche for the maintenance of memory cells at the local level. These data show that SLOs are dispensable for the maintenance of immunologic memory and directly demonstrate the utility of local tissues, such as iBALT, in secondary immune responses.
authors.affiliation: Trudeau Institute, Saranac Lake, New York 12983, USA.
authors.forename: Juan E
authors.initials: JE
authors.lastname: Moyron-Quiroz
authors.forename: Javier
authors.initials: J
authors.lastname: Rangel-Moreno
authors.forename: Louise
authors.initials: L
authors.lastname: Hartson
authors.forename: Kim
authors.initials: K
authors.lastname: Kusser
authors.forename: Michael P
authors.initials: MP
authors.lastname: Tighe
authors.forename: Kimberly D
authors.initials: KD
authors.lastname: Klonowski
authors.forename: Leo
authors.initials: L
authors.lastname: Lefrançois
authors.forename: Linda S
authors.initials: LS
authors.lastname: Cauley
authors.forename: Allen G
authors.initials: AG
authors.lastname: Harmsen
authors.forename: Frances E
authors.initials: FE
authors.lastname: Lund
authors.forename: Troy D
authors.initials: TD
authors.lastname: Randall
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001980:Bronchi / Q000166:cytology / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory; D007251:Influenza, Human / Q000276:immunology; D008221:Lymphoid Tissue / Q000166:cytology / Q000276:immunology*; D051379:Mice; D009975:Orthomyxoviridae / Q000276:immunology
chemical_list: D000914:Antibodies, Viral