The TCR assigns naive T cells to a preferred lymph node.

Area of Science:

• Immunology
• T cell biology
• Lymphocyte trafficking

Background:

• Naive T cells recirculate between lymphoid organs to encounter foreign antigens presented by dendritic cells.
• The random distribution of T cells is assumed to ensure exposure to all lymph nodes for immune surveillance.

Purpose of the Study:

• To investigate the distribution patterns and potential antigen-driven selection of naive T cells within different lymph nodes.
• To explore the implications of localized T cell interactions on immune homeostasis.

Main Methods:

• Deep sequencing of T cell receptor (TCR) repertoires to analyze T cell populations across multiple lymph nodes in individual mice.
• Utilizing TCR-transgenic mouse models to track T cell behavior, including CD69 expression, retention, and proliferation, in response to localized stimuli.

Main Results:

• Evidence for a deterministic CD4/CD8 lineage choice and a consistent spatial organization of T cells within the lymphatic system.
• Identification of specific naive T cell populations demonstrating preference for particular lymph nodes, suggesting interaction with local self-peptides.
• TCR-transgenic models confirmed localized retention and cell division of T cells in specific niches.

Conclusions:

• Naive T cells do not distribute randomly but rather sense and respond to antigenically distinct microenvironments within lymph nodes.
• This intermittent sensing of dissimilar niches influences T cell homeostasis and competitive interactions, impacting immune system regulation.