Diversification of CD1 Molecules Shapes Lipid Antigen Selectivity

Area of Science:

• Immunology
• Evolutionary Biology
• Molecular Biology

Background:

• Molecular studies of host-pathogen evolution often overlook microbe-associated macromolecules.
• The Cluster of Differentiation 1 (CD1) family of receptors presents lipid antigens to T-cells, crucial for adaptive immunity.
• CD1 diversity in vertebrates is lower than Major Histocompatibility Complex (MHC) molecules.

Purpose of the Study:

• Investigate the evolutionary dynamics of CD1 genes in primates.
• Determine how CD1 genetic variation impacts lipid-binding properties and T-cell receptor interactions.
• Explore the role of lipid-protein interactions in host-pathogen conflict and immune evolution.

Main Methods:

• Comparative genomic analysis of CD1 genes across simian primate species.
• Molecular modeling to predict the effects of CD1 variation on lipid binding and T-cell recognition.
• Analysis of positive selection signatures on CD1 family proteins.
• Functional assays to assess the impact of CD1 alterations on antigen swapping and T-cell activation.

Main Results:

• CD1 genes show significant divergence between primate species, altering predicted lipid-binding and T-cell interactions.
• Positive selection is evident on CD1 surfaces involved in antigen presentation, binding pocket structure, and T-cell receptor accessibility.
• Interspecies variation and specific mutations in CD1a drastically change lipid-binding affinities and T-cell recognition surfaces.
• Altered lipid-binding affinities of CD1a impact antigen swapping essential for T-cell activation.

Conclusions:

• Lipid-protein interactions are a critical evolutionary force in host-pathogen conflict, shaping CD1 genetic variation.
• Rapid evolution of CD1 suggests an ongoing arms race involving lipid antigens.
• Understanding these dynamics can inform the development of novel lipid-based vaccines.