Engineering high-fidelity tapasin variants to enhance MHC-I antigen presentation.

Area of Science:

• Immunology
• Molecular Biology
• Protein Engineering

Background:

• Human leukocyte antigen (HLA) proteins are highly polymorphic and rely on the chaperone tapasin for proper function.
• Tapasin downregulation in viral infections and cancers impairs antigen presentation, hindering therapeutic strategies.

Purpose of the Study:

• To investigate the mutational tolerance of tapasin surfaces interacting with HLA residues.
• To engineer enhanced tapasin variants for improved HLA expression and peptide loading.

Main Methods:

• Utilized deep mutational scanning to map the tapasin/HLA-A*02:01 interaction landscape.
• Engineered and tested novel tapasin variants (tapasin-YTY and tapasin-I2).

Main Results:

• Identified key regions critical for HLA class I assembly and repertoire optimization.
• Engineered tapasin variants increased cell surface HLA expression by up to 50% in tapasin-deficient cells.
• Demonstrated improved peptide loading function across multiple HLA-A* allotypes.

Conclusions:

• Scanning mutagenesis is a viable approach to fine-tune chaperone-HLA interactions.
• Engineered tapasin variants enhance antigen presentation in immune-impaired conditions.