Framework engineering to produce dominant T cell receptors with enhanced antigen-specific function.

Area of Science:

• Immunology
• Molecular Biology
• Biotechnology

Background:

• T-cell receptor (TCR) gene transfer generates therapeutic T cells with specific antigen recognition.
• Variations in human TCR cell surface expression can limit the efficacy of engineered T cells.

Purpose of the Study:

• To investigate amino acid substitutions in TCR variable domains to enhance TCR surface expression and improve T cell function.
• To establish a generic platform for optimizing TCR gene therapy.

Main Methods:

• Engineered T cells with modified TCR variable domains were generated by substituting 3 amino acid residues.
• Assessed cell surface expression levels of modified TCRs.
• Evaluated T cell proliferation, cytokine production, and cytotoxicity.
• Performed adoptive transfer experiments in mouse models to assess tumor control.

Main Results:

• Substitutions in TCR variable domain frameworks consistently increased human TCR surface expression.
• Modified TCRs demonstrated enhanced T cell proliferation, cytokine production, and cytotoxicity.
• Reduced peptide concentration required for effector function triggering (up to 3000-fold).
• Modified TCRs showed more efficient tumor growth control in vivo compared to wild-type TCRs.

Conclusions:

• Simple TCR variable domain modifications, distant from antigen-binding sites, can significantly increase TCR expression.
• Enhanced TCR expression leads to improved T cell effector functions and therapeutic efficacy.
• This strategy provides a versatile platform for advancing TCR gene therapy for various diseases.