Does memory improve with age? CD85j (ILT-2/LIR-1) expression on CD8 T cells correlates with 'memory inflation' in human cytomegalovirus infection.
Level 4 - case-series / case-control
Cross-sectional observational study using human blood samples and multivariate regression modeling.
PubMed 15748215 · doi:10.1111/j.1440-1711.2005.01321.x
What was done
Peripheral blood samples from human subjects across various ages were analyzed using tetramer staining and multivariate regression to examine the phenotype of CMV-specific and total CD8+ T cells, focusing on CD85j (ILT-2/LIR-1), CD57, and CCR7 expression in relation to CMV-induced memory inflation.
What was found
CD85j was highly co-expressed with CD57 on CMV-specific CD8+ T cells. Across all CD8+ T cells, advancing age was associated with increased CD57 and CD85j expression alongside decreased CCR7 expression. Incremental increases in the proportion of CMV-specific CD8+ T cells expressing CD57 and CD85j correlated with the expansion of these populations. At any given age, CMV seropositivity was associated with an 18.7% increase in CD85j expression, corresponding to an estimated apparent immune aging effect of 35.4 years.
Why it matters
This study quantifies the substantial phenotypic shift in the CD8+ T-cell compartment driven by latent CMV infection, framing memory inflation as a linear, progressive maturation process.
Limits
The abstract does not disclose the exact sample size or demographic characteristics of the participants. The cross-sectional design models aging without direct longitudinal tracking, and functional immune competence or clinical endpoints were not measured.
Cited by
- supports In old age, individuals accumulate CMV-specific T cells, which in some individuals can expand to occupy 20% to 30% of all T cells dedicated to a single CMV peptide.