Aging trajectories of memory CD8 ⁺ T cells differ by their antigen specificity

Area of Science:

• Immunology
• Gerontology
• Infectious Disease

Background:

• Memory T cells are crucial for adaptive immunity but their function is affected by aging.
• Aging can lead to T cell dysfunction, but the specific impact on antigen-specific memory T cells remains unclear.
• Heterogeneity in memory T cell populations complicates the study of aging effects.

Purpose of the Study:

• To investigate how aging influences the memory states of antigen-specific CD8+ T cells.
• To assess the impact of age on T cell differentiation and function in the context of chronic Epstein-Barr virus (EBV) infection.
• To identify age-associated changes in gene expression and T cell receptor diversity.

Main Methods:

• Analysis of EBV-specific CD8+ T cells in young (<40 years) and older (>65 years) adults.
• Assessment of T cell differentiation states based on peptide specificity.
• Evaluation of gene expression, T cell receptor diversity, and immune signatures (adaptive vs. innate).

Main Results:

• In young adults, EBV-specific CD8+ T cells showed preferred differentiation states.
• In older adults, distinct aging trajectories were observed for different T cell specificities.
• Common age-associated changes included a loss of adaptive and a gain of innate immunity signatures, with no signs of senescence or exhaustion.
• Naïve/stem-like T cells decreased with age, while overall T cell diversity of EBV-specific memory cells remained stable or increased.

Conclusions:

• Antigen specificity is critical for understanding age-associated T cell changes.
• Aging drives shifts in gene expression and T cell receptor diversity in memory T cells.
• Findings have implications for improving vaccination strategies and adoptive T cell therapies in aging populations.