Because of their importance in cell signaling and human disease, integral membrane proteins such as G protein-coupled receptors (GPCRs) and ion channels comprise over 40% of existing drug targets. Monoclonal antibodies (MAbs) that recognize conformation-dependent epitopes on membrane proteins are usually the most valuable type of antibody because they often bind to critical structures of the receptor that can be exploited for its detection or inhibition. However, the development of conformation-dependent, inhibitory MAbs against membrane proteins is especially difficult because, unlike soluble proteins, most membrane proteins are dependent on a lipid environment to maintain their native tertiary and quaternary (oligomeric) structures. Membrane proteins are often difficult to purify, often express at low concentrations on the cell surface, and are usually poorly represented by linear peptides. New approaches are needed to develop such MAbs for therapeutic, diagnostic, and research applications. Here we propose to use a novel technology, the Lipoparticle, to capture and concentrate structurally intact membrane proteins in a format amenable to immunization. The concept of using Lipoparticles to develop antibodies against cellular membrane proteins builds on the historic use of viral particles as successful vaccines.
This proposal will result in monoclonal antibodies against important membrane protein targets for therapeutic development, diagnostics, and biomedical research. Lipoparticles optimized as immunogens will be developed as commercial products.
