Tissue-infiltrating alloreactive T cells require Id3 to deflect PD-1-mediated immune suppression during GVHD

Area of Science:

• Immunology
• Molecular Biology
• Cancer Immunotherapy

Background:

• Alloreactive donor T cells in target tissues drive graft-versus-host disease (GVHD).
• Transcriptional regulators controlling tissue-infiltrating T cells in GVHD are not well understood.
• Identifying these regulators is key to developing new GVHD therapies.

Purpose of the Study:

• To investigate the role of Id3 in T-cell persistence and function within GVHD target tissues.
• To explore Id3's impact on T-cell signaling pathways and its regulation of PD-1 expression.
• To assess the therapeutic potential of targeting Id3 for GVHD and T-cell-based immunotherapy.

Main Methods:

• Utilized mouse models of GVHD to study T-cell responses in liver and intestine.
• Employed single-cell RNA-sequencing and genome-wide RNA-sequencing to analyze gene expression and signaling.
• Investigated the effects of Id3 ablation and PD-1 blockade on T-cell function and GVHD severity.
• Assessed CRISPR/Cas9-mediated ID3 knockout in human CAR T cells for antitumor activity.

Main Results:

• Id3 deficiency led to aberrant PD-1 expression, reduced T-cell infiltration, and impaired T-cell maintenance in GVHD target tissues.
• Loss of Id3 decreased CD28 and PI3K/AKT signaling, indicating enhanced PD-1/PD-L1 pathway effects.
• Id3 ablation protected CD8+ T cells from PD-1-mediated suppression and preserved graft-versus-tumor effects.
• CRISPR/Cas9 knockout of ID3 in CAR T cells maintained antitumor activity.

Conclusions:

• Id3 is essential for sustaining T-cell responses and preventing GVHD by repressing key transcription factors involved in T-cell activation and dysfunction.
• Targeting Id3 represents a promising strategy to mitigate GVHD.
• Gene editing of ID3 holds potential for enhancing T-cell-based immunotherapies, including CAR T-cell therapy.