Vaccinex has developed technologies to enable antibody discovery vs complex antigens such as GPCRs using both in vitro and in vivo antibody discovery platforms.
Our Activmab fusion protein technology enables the direct incorporation of multi-pass membrane proteins such as GPCRs and ion channels into the membrane of two antigenically distinct poxviruses. The protein of interest is correctly folded and expressed in the cell-derived viral membrane.  The antigen expressing virus can be readily purified via a simple centrifugation step and there is no need for any detergents or refolding before downstream use. Antigen virus is much cleaner than Virus Like Particles because of its specific membrane complexity. Our Biosafety Level 1 antigen virus particles (VPs) can be directly coated onto ELISA plates, coupled to magnetic beads, or used for FACS sorting and are compatible with both phage and yeast display.  Additionally, we have two antigenically distinct strains which can drive antigen specificity in the discovery process. 
Antigen virions can also be used for in vivo antibody discovery methods. Immunization with either viral strain produces potent antibody responses. The resulting immune cells can then be used for Single B Cell sorting, Plasma Cell interrogation, or to create an immunized phage library for in vitro panning with antigen virus made in the antigenically distinct strain.