Reprogramming CD8+ T-cell Branched N-Glycosylation Limits Exhaustion, Enhancing Cytotoxicity and Tumor Killing

Area of Science:

• Immunology
• Glycobiology
• Cancer Biology

Background:

• T-cell therapies are crucial for cancer treatment.
• The role of cell surface glycans in T-cell function and tumor immunity is under investigation.
• Intratumoral T-cell glycomes are altered in early colorectal cancer.

Purpose of the Study:

• To investigate the influence of the glycome on T cell-mediated tumor immunity.
• To identify specific glycan alterations in intratumoral T cells.
• To determine the role of Mgat5 in T-cell exhaustion and anti-tumor activity.

Main Methods:

• Analysis of intratumoral T-cell glycomes in colorectal cancer.
• Assessment of T-cell phenotypes, including PD1 and Tim3 expression.
• CRISPR/Cas9 gene editing to delete Mgat5 in T cells.
• In vitro and in vivo assays evaluating T-cell killing of cancer cells.
• Engineering of anti-CD19 chimeric-antigen receptor (CAR) T cells with MGAT5 knockout.

Main Results:

• Early colorectal cancer shows significant changes in branched N-glycans on intratumoral T cells.
• CD8+ T cells with β1,6-GlcNAc branched N-glycans exhibit an exhausted phenotype (increased PD1, Tim3).
• Mgat5 deletion in CD8+ T cells improves cancer cell killing.
• MGAT5 knockout anti-CD19-CAR T cells inhibit the growth of CD19-transduced tumors.

Conclusions:

• MGAT5-mediated branched N-glycans are key regulators of CD8+ T-cell function in cancer.
• Targeting Mgat5 offers a strategy to enhance the anti-tumor activity of both native and CAR T cells.
• Glycan engineering presents a promising approach to improve T-cell immunotherapy efficacy.