Respiratory syncytial virus-specific CD8+ memory T cell responses in elderly persons

Abstract

Background. We investigated respiratory syncytial virus (RSV)-specific CD8+ memory T cell responses in healthy control participants (n = 31) and in patients with chronic obstructive pulmonary disease (COPD) (n = 9), with respect to frequency, memory phenotype, and proliferative requirements. Methods. The properties of RSV-specific CD8+ T cells were analyzed by use of RSV tetramers. The proliferative requirements of RSV-specific CD8 + T cells were analyzed by culture of peripheral-blood mononuclear cells with RSV peptide in combination with distinct cytokines. Results. RSV-specific CD8+ memory T cells showed a high level of expression of CD27 and interleukin-7Rα and a low level of expression of CCR7. In the healthy participants, the frequency of RSV tetramer+ CD8+ T cells was significantly lower than the frequency of influenza virus A (FLU) tetramer+ CD8+ T cells (P = .0001). In contrast to FLU tetramer+ CD8+ T cells, we could detect RSV tetramer + CD8+ T cells in the subgroup of elderly healthy participants (age, ≥55 years) and in the patients with COPD only after in vitro expansion. Expanded RSV-specific T cells produced interferon-γ and granzyme B. Conclusion. We provide evidence that a pool of functional RSV-specific CD8+ memory T cells persists in the peripheral blood of healthy individuals and patients with COPD. Low numbers of RSV-specific memory T cells in the elderly and in patients with COPD may explain the increased susceptibility to RSV infection in these populations. © 2005 by the Infectious Diseases Society of America. All rights reserved.