title: Diminished influenza A virus-specific MHC class I-restricted cytotoxic T lymphocyte activity among elderly persons.
abstract: Influenza A virus-specific MHC class I-restricted cytotoxic T lymphocyte (CTL) activities among young and elderly adults were compared. Peripheral blood lymphocytes from 10 young adults, (mean age 27 +/- 2.4 years) and elderly persons (mean age 71 +/- 1.6 years) were stimulated with influenza A/Taiwan/1/86 (H1N1) virus for 7 days and assayed for lytic activity against A/Taiwan, A/Shanghai (H3N2), and B/USSR virus-infected autologous target cells. Young adults exhibited significantly higher influenza A cross-reactive CTL activity against A/H1N1 and A/H3N2 target cells when compared to aged persons. This was true at all effector-to-target cell ratios tested. Negligible lysis of B/USSR-infected target cells or nonautologous A/Taiwan-infected cells was observed. The number of leukocytes recovered per milliliter of blood was also significantly higher in young adults than in old donors; however, the percentage of CD45+ (common leukocyte antigen), CD3+ (T cells), CD4+ (T helper), and CD8+ (T cytotoxic/suppressor) as well as the CD4+/CD8+ ratios was similar in both groups. Depletion of cells with monoclonal antibodies indicated that the effector cells were CD8+ T cells. Serum-neutralizing antibody (Nt Ab) titers were similar among young and elderly persons and there was no correlation between Nt Ab and CTL activity. These results demonstrate a reduced influenza virus-specific MHC class I-restricted CTL activity among elderly persons. The deficiency in this cell-mediated immune function may contribute to the morbidity and mortality from influenza virus infections in this population.
authors: Department of Microbiology and Immunology, Baylor College of Medicine, Houston, Texas 77030.
authors: I N
authors: IN
authors: Mbawuike
authors: A R
authors: AR
authors: Lange
authors: R B
authors: RB
authors: Couch
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000096:biosynthesis; D015703:Antigens, CD / Q000032:analysis; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D007111:Immunity, Cellular; D016130:Immunophenotyping; D009980:Influenza A virus / Q000276:immunology*; D007958:Leukocyte Count; D008297:Male; D016176:T-Lymphocyte Subsets; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D015703:Antigens, CD; D015395:Histocompatibility Antigens Class I