Distinct transcriptomic and epigenomic modalities underpin human memory T cell subsets and their activation potential

Area of Science:

• Immunology
• Epigenetics
• Cellular Metabolism

Background:

• Human memory T cells (MTC) are crucial for adaptive immunity, providing rapid responses upon antigen re-exposure.
• Understanding the molecular basis of MTC function is key to developing effective immunotherapies and vaccines.

Purpose of the Study:

• To delineate the transcriptional and epigenetic landscapes of resting and activated human CD4+ and CD8+ MTC subsets.
• To identify molecular mechanisms underlying MTC preparedness and enhanced responsiveness.

Main Methods:

• Analysis of transcriptional and epigenetic programs in circulating CD4+ and CD8+ MTC subsets.
• Assessment of chromatin accessibility, transcription factor binding motifs, and gene expression patterns.
• Investigation of metabolic adaptations and epigenetic priming in MTCs.

Main Results:

• A gradient of gene expression and chromatin accessibility from naive to central memory (TCM) to effector memory (TEM) T cells was observed.
• Distinct accessible chromatin patterns, transcription factor motifs (AHR, HIF1A), and epigenetic priming were identified in MTC subsets.
• Stimulation led to augmented MTC gene expression and effector transcription factor expression, correlated with primed accessible chromatin.

Conclusions:

• Coordinated epigenetic remodeling, metabolic adaptations, and transcriptional changes enable MTC subsets to respond more efficiently to antigen re-encounters.
• Epigenetic priming and specific transcription factor networks play critical roles in MTC function and environmental sensing.