Engineering improved T cell receptors using an alanine-scan guided T cell display selection system

Area of Science:

• Immunology
• Molecular Biology
• Biotechnology

Background:

• T cell receptors (TCRs) recognize peptide-major histocompatibility complex (pMHC) to initiate immune responses.
• Naturally occurring TCRs have low affinity for self-antigens like tumor peptides, complicating cancer immunotherapy.
• Engineering high-affinity TCRs in vitro is challenging due to limited knowledge of TCR-pMHC interactions.

Purpose of the Study:

• To develop a method for efficiently engineering high-affinity TCRs for enhanced adoptive immunotherapy.
• To identify key amino acid residues involved in TCR-pMHC binding for targeted TCR library design.

Main Methods:

• Utilized a mammalian retroviral display system for direct comparison of TCR-pMHC binding and T cell activation.
• Employed an alanine-scanning approach to map critical TCR-pMHC interaction residues.
• Designed and selected TCR libraries based on identified key residues.

Main Results:

• Identified key binding residues within the CDR3β region of a self-antigen-specific human TCR (R6C12).
• Demonstrated that targeting specific TCR residues enables the design of libraries yielding TCRs with higher avidity.
• Selected TCRs exhibited enhanced binding and activation compared to wild-type.

Conclusions:

• Alanine scanning combined with mammalian retroviral display efficiently maps TCR-pMHC interaction sites.
• Targeted engineering of TCR libraries based on identified residues can generate high-avidity TCRs.
• This approach offers a direct strategy to develop TCRs for improved adoptive immunotherapy treatments.