Cell surface expression and function of an HLA class II molecule with class I domain configuration

Area of Science:

• Immunology
• Molecular Biology
• Structural Biology

Background:

• Major Histocompatibility Complex (MHC) molecules present peptides to T cells, playing a crucial role in adaptive immunity.
• MHC class I and class II molecules have distinct structures and functions, but share evolutionary origins.
• Understanding MHC structure is key to developing immunotherapies and vaccines.

Purpose of the Study:

• To engineer recombinant MHC class II molecules with reorganized extracellular domains analogous to MHC class I.
• To assess the functional capacity of these domain-shifted MHC class II constructs.
• To explore the evolutionary relationship between MHC class I and II through structural manipulation.

Main Methods:

• Recombinant expression of MHC class II extracellular domains into heavy (H) and light (L) chains.
• Construction of a 3+1-DR1 chimera mimicking class I domain organization.
• Assessment of protein folding, dimerization, peptide-binding affinity, and T cell stimulation assays.

Main Results:

• Successful expression and folding of recombinant MHC class II H and L chains.
• Demonstrated peptide-binding capability of the 3+1-DR1 construct to class II-restricted peptides.
• Functional stimulation of CD4+ T cells by the engineered MHC class II molecule, confirming cell surface expression and activity.

Conclusions:

• The study validates current models of MHC class II structure and function.
• The findings affirm the evolutionary relatedness of MHC class I and II molecules.
• Domain configuration may influence distinct MHC functions, offering new avenues for research using domain-shifted constructs.