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

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-7R alpha 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-gamma 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.