Naive CD8⁺ T-cell precursors display structured TCR repertoires and composite antigen-driven selection dynamics

Area of Science:

• Immunology
• T-cell biology
• Human immunology

Background:

• The baseline characteristics of the naive antigen-specific T-cell repertoire in humans are not well understood.
• Comparing naive T-cells to memory T-cells is essential for understanding immune responses and clonal selection.
• Characterizing the 'ground state' immunity provides a foundation for studying immune challenges.

Purpose of the Study:

• To systematically define the frequency, phenotype, and T-cell antigen receptor (TCR) repertoire of naive CD8(+) T-cell precursor populations in human umbilical cord blood.
• To compare the naive T-cell repertoire with adult memory T-cells to understand repertoire structuring.
• To gain insights into the dynamics of the naive T-cell compartment.

Main Methods:

• High-definition cell isolation from umbilical cord blood samples.
• Analysis of CD8(+) T-cell precursor populations specific for viral and self-derived antigens.
• Characterization of T-cell antigen receptor (TCR) repertoire architecture and T-cell phenotypes.

Main Results:

• Naive T-cell precursor populations specific for various antigens were identified with hierarchical frequencies.
• These precursor populations exhibited naive phenotypes and clustered by antigen specificity.
• The TCR repertoire architecture was highly ordered and showed partial overlap with adult memory T-cells, suggesting biased repertoire structuring.

Conclusions:

• The study provides a comprehensive baseline characterization of the naive T-cell repertoire in humans.
• Findings indicate a structured and biased organization of the naive T-cell compartment, influenced by antigen-driven selection.
• This research offers new insights into the complex dynamics of naive T-cells and their relationship with memory T-cells.