title: Age-related changes in memory and effector T cells responding to influenza A/H3N2 and pandemic A/H1N1 strains in humans.
abstract: Age-dependent changes in the cellular immune response have been mainly described in CD8+ T cells, with relative sparing of CD4+ T cells. We show that in older compared to young adults, effector memory and effector CD8+ T-cell subsets responding to influenza A/H3N2 challenge have diminished cytolytic activity. In contrast, effector CD4+ T-cell subsets in older adults share similar phenotypic and functional characteristics with those from young adults. Further, we observed a diminished cytolytic T-cell response to both seasonal influenza A/H3N2 and pandemic H1N1 (pH1N1) strains in older compared to young adults who had received seasonal influenza vaccine. These results are consistent with the observed rates of serious complications from seasonal and pandemic influenza infections in different age groups, and suggest that CD4+ T cells may provide a compensatory response to influenza infection when CD8+ T cells become compromised during the aging process.
authors.affiliation: Center for Immunotherapy of Cancer and Infectious Diseases, Department of Immunology, University of Connecticut School of Medicine, Farmington, CT 06030-1601, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.forename: Janet E
authors.initials: JE
authors.lastname: McElhaney
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D053804:Granzymes / Q000276:immunology; D006801:Humans; D007111:Immunity, Cellular; D007156:Immunologic Memory; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage; D007251:Influenza, Human / Q000276:immunology*; D008875:Middle Aged; D054353:Perforin / Q000276:immunology; D010641:Phenotype; D016176:T-Lymphocyte Subsets / Q000276:immunology; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines; D054353:Perforin; D053804:Granzymes