Decoupling peptide binding from T cell receptor recognition with engineered chimeric MHC-I molecules.

Area of Science:

• Immunology
• Structural Biology
• Computational Biology

Background:

• Major Histocompatibility Complex class I (MHC-I) molecules present peptides to T cell receptors (TCRs) for immune recognition.
• Human Leucocyte Antigen (HLA) polymorphism influences peptide and TCR binding within a conserved structural framework.
• Understanding these interactions is crucial for developing targeted immunotherapies.

Purpose of the Study:

• To engineer novel synthetic MHC-I molecules with combined peptide-binding and TCR-recognition properties.
• To investigate the role of HLA framework residues versus peptide interactions in TCR recognition.
• To establish a structure-guided platform for creating custom MHC-I-based screening probes.

Main Methods:

• Utilized structural data from peptide:MHC-I and pMHC:TCR complexes.
• Employed a fixed-backbone computational design approach to engineer chimeric MHC-I molecules.
• Validated molecular designs using X-ray crystallography, in vitro tetramer staining, and biophysical binding assays.

Main Results:

• Successfully engineered chimeric MHC-I molecules bridging divergent HLA alleles capable of binding specific peptide antigens.
• Demonstrated that TCR recognition relies on interactions with HLA framework residues, not solely peptide-centric interactions.
• Confirmed the requirement of HLA framework residue engagement for effective TCR binding.

Conclusions:

• Developed a novel, structure-guided platform for creating synthetic MHC-I molecules.
• These engineered molecules serve as valuable screening probes for studying peptide-TCR interactions.
• The findings advance the development of therapeutic modalities targeting T cell recognition.