TY - JOUR T1 - Construction, characterization, and immunization of nanoparticles that display a diverse array of influenza HA trimers JF - bioRxiv DO - 10.1101/2020.01.18.911388 SP - 2020.01.18.911388 AU - Alexander A. Cohen AU - Zhi Yang AU - Priyanthi Gnanapragasam AU - Susan Ou AU - Kim-Marie Dam AU - Haoqing Wang AU - Pamela J. Bjorkman Y1 - 2020/01/01 UR - http://biorxiv.org/content/early/2020/01/19/2020.01.18.911388.abstract N2 - Current influenza vaccines do not elicit broadly protective immune responses against multiple strains. New strategies to focus the humoral immune response to conserved regions on influenza antigens are therefore required for recognition by broadly neutralizing antibodies. It has been suggested that B cells with receptors that recognize conserved epitopes would be preferentially stimulated through avidity effects by mosaic particles presenting multiple forms of a variable antigen. We adapted SpyCatcher-based platforms, AP205 virus-like particles (VLPs) and mi3 nanoparticles (NPs), to covalently co-display SpyTagged hemagglutinin (HA) trimers from different influenza strains. Here we show successful homotypic and heterotypic conjugation of up to 8 different HA trimers to both VLPs and NPs, and demonstrate that conjugated particles were stable for several weeks of storage. We characterized the HA-VLPs and HA-NPs by cryo-electron tomography to derive the average number of conjugated HAs and their separation distances, and compared immunizations of mosaic and homotypic particles in wild-type mice. Both types of HA particles elicited strong antibody responses, but the mosaic particles did not consistently elicit broader immune responses. We conclude that covalent attachment of HAs from currently-circulating influenza strains represents a viable alternative to current annual influenza vaccine strategies, but in the absence of further modifications, is unlikely to represent a method for making a universal influenza vaccine. ER -