title: Role of humoral and cell-mediated immunity in protection from influenza disease after immunization of healthy elderly.
abstract: While influenza immunization significantly reduces the risk of pneumonia and associated deaths, vaccination of elderly only affords 30-50% protection against influenza disease. The purpose of this study was to: (1) evaluate the consistency of immune responses across multiple years in young and elderly; (2) determine the contribution of antibody and cell-mediated responses in protection after immunization with influenza vaccine. Independently living healthy elderly (>200/year; mean age 78.8-80.6/year) were recruited yearly in this four year study. The results clearly demonstrate: (1) both young and elderly consistently produced significant antibody and T cell proliferative responses to influenza vaccine upon yearly immunization; however, both responses of elderly were significantly and consistently lower than young. (2) Percentages of both young and elderly demonstrating protective titers (i.e. HI>/=40) increased post-immunization each year, but were consistently higher in young compared to elderly. (3) The risk of developing influenza disease after immunization was highest among elderly demonstrating neither antibody nor cell-mediated responses. Importantly, the risk of influenza disease was comparable in elderly demonstrating a cell-mediated response alone, an antibody response alone, or both cell-mediated and antibody responses. This suggests that cell-mediated responses play a significant role in protection in at least a subset of elderly from influenza disease after immunization.
authors.affiliation: Department of Microbiology and Immunology, MCP Hahnemann University School of Medicine and Public Health, 2900 Queen Lane, Philadelphia, PA 19129, USA. donna.murasko@drexel.edu
authors.forename: Donna M
authors.initials: DM
authors.lastname: Murasko
authors.forename: Erica D
authors.initials: ED
authors.lastname: Bernstein
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Gardner
authors.forename: Peter
authors.initials: P
authors.lastname: Gross
authors.forename: Gary
authors.initials: G
authors.lastname: Munk
authors.forename: Sandra
authors.initials: S
authors.lastname: Dran
authors.forename: Elias
authors.initials: E
authors.lastname: Abrutyn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000276:immunology*; D000917:Antibody Formation; D005260:Female; D006304:Health Status; D006801:Humans; D007111:Immunity, Cellular; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology* / Q000517:prevention & control; D007371:Interferon-gamma / Q000097:blood; D007376:Interleukin-2 / Q000097:blood; D008297:Male; D012107:Research Design; D014611:Vaccination
chemical_list: D007252:Influenza Vaccines; D007376:Interleukin-2; D007371:Interferon-gamma