Phenotypic classification of human CD8+ T cells reflecting their function: inverse correlation between quantitative...

Area of Science:

• Immunology
• Cell Biology

Background:

• CD8(+) T cell classification using CD27, CD28, and CD45RA markers is proposed for identifying naive, memory, and effector cells.
• The functional relevance of this phenotypic classification for CD8(+) T cells requires further clarification.

Purpose of the Study:

• To determine if phenotypic classification of CD8(+) T cells using CD27, CD28, and CD45RA accurately reflects their functional states.
• To refine the phenotypic classification for a more precise reflection of CD8(+) T cell function.

Main Methods:

• Characterization of CD27, CD28, and CD45RA subsets of total and human cytomegalovirus (HCMV)-specific CD8(+) T cells.
• Analysis of perforin, CCR5, and CCR7 expression, alongside functional assays.
• Division of the CD27(+) subset into CD27(low) and CD27(high) based on expression levels.

Main Results:

• An inverse correlation was observed between perforin expression and CD27 expression across CD28/CD45RA subsets.
• The refined phenotypic classification, incorporating CD27 expression levels, demonstrated a strong correlation with functional classification of CD8(+) T cells.
• HCMV-specific CD8(+) T cells in seropositive individuals were primarily located in effector and memory/effector subsets.

Conclusions:

• A refined phenotypic classification of CD8(+) T cells, incorporating CD27 expression levels, accurately reflects their functional states.
• This classification is valuable for characterizing antigen-specific CD8(+) T cells, including those responding to HCMV.
• HCMV replication actively induces HCMV-specific effector CD8(+) T cells in healthy carriers.