Rantalainen, K.; Liguori, A.; Ozorowski, G.; Flynn, C.; Steichen, J. M.; Swanson, O.; Madden, P. J.; Baboo, S.; Phulera, S.; Gharpure, A.; Lu, D.; Kalyuzhniy, O.; Skog, P.; Terada, S.; Shil, M.; Diedrich, J. K.; Georgeson, E.; Tingle, R.; Eskandarzadeh, S.; Lee, W.-H.; Goodwin, D.; Alavi, N.; Kubitz, M.; Amirzehni, S.; Himansu, S.; Sok, D.; Lee, J. H.; Yates, J. R.; Paulson, J. C.; Crotty, S.; Schiffner, T.; Ward, A. B.; Schief, W. R.

Transmembrane glycoproteins of enveloped viruses are the targets of neutralizing antibodies and essential vaccine antigens. mRNA-LNP technology allows in situ production of transmembrane glycoproteins upon immunization, but biophysical characterization of transmembrane antigens and in vitro analysis of post-immunization antibody responses typically rely on soluble proteins. Here, we present a methodological platform for assembling transmembrane glycoprotein vaccine candidates into lipid nanodiscs. We demonstrate the utility of the nanodiscs in HIV membrane proximal external region (MPER)-targeting vaccine development by binding assays using surface plasmon resonance (SPR), ex vivo B cell sorting with fluorescence-activated cell sorting (FACS), and by determining the structure of a prototypical HIV MPER-targeting immunogen nanodisc in complex with three broadly neutralizing antibodies (bnAbs), including the MPER bnAb 10E8, to 3.5 [A] by cryogenic electron microscopy (cryo-EM), providing a template for structure-based immunogen design for MPER. Overall, the platform offers a tool for accelerating the development of next-generation viral vaccines.