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

Area of Science:

• Immunology
• Virology
• Respiratory Medicine

Background:

• Investigated respiratory syncytial virus (RSV)-specific CD8(+) memory T cell responses.
• Compared responses in healthy individuals (n=31) and chronic obstructive pulmonary disease (COPD) patients (n=9).
• Assessed frequency, memory phenotype, and proliferative needs of these T cells.

Purpose of the Study:

• To characterize RSV-specific CD8(+) memory T cell populations.
• To determine if these cells are diminished in elderly individuals and COPD patients.
• To understand the implications for susceptibility to RSV infection.

Main Methods:

• Utilized RSV tetramers to analyze RSV-specific CD8(+) T cells.
• Cultured peripheral-blood mononuclear cells with RSV peptide and cytokines to assess proliferative requirements.
• Measured expression of CD27, interleukin-7R alpha, and CCR7.

Main Results:

• RSV-specific CD8(+) memory T cells expressed high CD27 and IL-7Rα, low CCR7.
• Frequencies of RSV-specific CD8(+) T cells were lower than influenza A virus (FLU)-specific cells in healthy individuals.
• RSV-specific CD8(+) T cells were detectable only after in vitro expansion in elderly and COPD patients.

Conclusions:

• A functional pool of RSV-specific CD8(+) memory T cells exists in healthy individuals and COPD patients.
• Reduced numbers of these cells in the elderly and COPD patients may contribute to increased RSV susceptibility.
• These findings highlight potential targets for improving immune responses against RSV.