Role of humoral and cell-mediated immunity in protection from influenza disease after immunization of healthy elderly

Exp Gerontol. Jan-Mar 2002;37(2-3):427-39. doi: 10.1016/s0531-5565(01)00210-8.


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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Aging / blood
  • Aging / immunology*
  • Antibody Formation
  • Female
  • Health Status
  • Humans
  • Immunity, Cellular
  • Influenza Vaccines / immunology*
  • Influenza, Human / immunology*
  • Influenza, Human / prevention & control
  • Interferon-gamma / blood
  • Interleukin-2 / blood
  • Male
  • Research Design
  • Vaccination


  • Influenza Vaccines
  • Interleukin-2
  • Interferon-gamma