HEB collaborates with TCR signaling to upregulate Id3 and enable γδT17 cell maturation in the fetal thymus.

Area of Science:

• Immunology
• Cell Biology
• Molecular Biology

Background:

• Gamma delta T cells (γδT17) producing IL-17 are vital for barrier immunity.
• The precise gene regulatory networks governing γδT17 cell function remain incompletely understood.
• Previous work linked T cell receptor (TCR) signal strength to Id3 expression and identified HEB as essential for γδT17 development.

Purpose of the Study:

• To elucidate the roles of HEB and Id3 in the developmental and functional programming of γδT17 cells.
• To investigate the regulatory relationship between HEB, Id3, and γδT17 cell differentiation.

Main Methods:

• Single-cell RNA sequencing was performed on fetal thymic γδ T cells from Tcf12 (HEB)-deficient mice.
• Analysis of γδ T cell development and gene expression in Id3-deficient mice.

Main Results:

• HEB deficiency profoundly altered TCRγ and TCRδ chain gene expression and early γδ T cell specification genes.
• HEB deficiency led to a significant decrease in Id3 expression, indicating HEB's role in its upregulation.
• Id3 deficiency did not affect TCR repertoires or early γδ T cell gene expression but decreased later-stage regulators and impaired IL-17 production.

Conclusions:

• HEB is initially required for upregulating Id3 expression during γδ T cell development.
• Id3 subsequently enables later stages of γδT17 cell differentiation and functional IL-17 production.
• This study reveals an interconnected gene network essential for γδT17 cell development and function in barrier immunity.