Rhesus Macaque Killer Cell Ig-like Receptor Domain 0 Glycans Impact Surface Expression and Ligand Specificity.

Area of Science:

• Immunogenetics
• NK cell biology
• Comparative immunology

Background:

• Killer cell Ig-like receptors (KIRs) are crucial for NK cell function.
• Rhesus macaque KIRs offer a model for studying infectious diseases and comparative immunogenetics.
• Specific KIRs in rhesus macaques possess a unique deletion in domain 0 (D0), affecting glycosylation sites near MHC class I binding regions.

Purpose of the Study:

• To investigate the role of N-linked glycosylation in rhesus macaque KIRs.
• To determine how D0 glycosylation affects KIR surface expression and ligand recognition.
• To elucidate the functional impact of polymorphic glycosylation sites in lineage II KIRs.

Main Methods:

• Construction of N-linked glycosylation (PNG) mutants for six lineage II KIR genes.
• Assessment of total and surface protein expression using immunoblotting and flow cytometry.
• Evaluation of ligand engagement via reporter cell assays and KIR-Fc fusion protein staining.

Main Results:

• N-linked glycosylation occurs at the single D0 site in KIRs with one site and at least one site in KIRs with two tandem sites.
• For KIRs with a single D0 glycosylation site, this site generally enhances surface expression.
• The first of two tandem D0 glycosylation sites can influence KIR-MHC class I ligand specificity.

Conclusions:

• D0 glycosylation significantly modulates surface expression of rhesus macaque KIRs.
• Glycosylation at D0 contributes to the specificity of KIR-MHC class I interactions.
• Understanding KIR glycosylation is key to NK cell biology in rhesus macaques.