Chemokine receptors CXCR4 or CXCR5 displayed on nanoparticles are bioactive and able to bind its relevant ligand CXCL12 or CXCL13 3085

Abstract Description The selective chemokine and receptor interactions are critical in inflammatory responses. CXCR4 is a receptor for chemokine CXCL12 and a co-receptor for HIV to infect CD4 T-cells. CXCR5 is a receptor for chemokine CXCL13. The overexpression of CXCR4 and CXCR5 on cancer cells make them attractive targets for therapeutics. As G protein-coupled seven transmembrane receptors, it is very challenging to generate bioactive chemokine receptor recombinant proteins with a native conformation. We engineered viral-like particles (VLPs) to display CXCR4 or CXCR5 with enhanced surface expression and embedded in the natural lipid bilayer as nanoparticles, CXCR4-CMP or CXCR5-CMP. The CXCR4 or CXCR5 nanoparticles were expressed using HEK293 cells. The purified nanoparticles were tested for size and morphology using electron-microscopy and dynamic light scattering. The target proteins were analyzed by multiple tests including antibody and ligand binding assays. Both CXCR4-CMP and CXCR5-CMP could bind potently to its specific antibody with EC50 values <100 ng/ml. More importantly, they could interact with their ligands as measured by ELISA. CXCR4-CMP could bind to its chemokine ligand CXCL12 and HIV-1 envelope glycoprotein gp120. CXCR5-CMP could bind to its chemokine ligand CXCL13. The results imply that these innovative CXCR4 and CXCR5 nanoparticles are bioactive and can potentially be used to evaluate the chemokine/receptor interactions and as an antigen for drug discovery. Topic Categories Cytokines and Chemokines and Their Receptors (CCR)