Generation of Conformation-Specific Monoclonal Antibodies for Integral Membrane Proteins

Antibodies and their antigen-binding fragments, including fragment antigen-binding domains (Fabs) and single-chain variable fragments (scFvs), are extraordinary tools in all fields of biology, particularly in neuroscience, where they have been utilized for imaging, detection, and quantification studies. Most antibodies bind to unstructured or linear epitopes. Conformation-specific antibodies, by contrast, bind to 3D epitopes, recognizing native conformations of the target antigen, and have proven highly useful in X-ray crystallography as crystallization chaperones and in cryo-electron microscopy as fiducial markers. Moreover, because conformation-specific antibodies recognize 3D shapes of the antigen, they often have exquisite specificity and are useful in immunofluorescence studies and in isolation of antigen from native tissues. Over the past decade, our group has devoted effort to developing murine monoclonal antibodies (mAbs) against important synaptic receptors, particularly ionotropic glutamate receptors (iGluRs) and their auxiliary proteins. We have developed reproducible methods for generating high-quality mAbs for structural, biochemical, and imaging studies. In this article, we show how to prepare proteoliposomes (PLs), carry out immunization and track the immune response, perform hybridoma generation, and analyze the specificity, cross-reactivity, and competition of mAb binding via enzyme-linked immunosorbent assay and fluorescence-detection size-exclusion chromatography. Our PL-based method produces high-affinity, conformation-specific antibodies targeting diverse synaptic membrane receptors in 4 months. Here, we describe the relevant protocols in detail and document the mAbs, Fabs, and scFvs that we have produced against iGluRs and their auxiliary subunits. © 2025 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Generation of conformation-specific antibodies for integral membrane proteins Support Protocol 1: Detection of conformational antibodies using ELISA Basic Protocol 2: Expression and purification of monoclonal antibodies and their derivatives Support Protocol 2: Concentration and clarification of insect cell supernatant for Fab purification Support Protocol 3: Measurement of ionotropic glutamate receptor binding kinetics using Octet BLI System.