Design and lyophilization of lipid nanoparticles for mRNA vaccine and its robust immune response in mice and nonhuman primates

Yuta Suzuki; Takayuki Miyazaki; Hiroki Muto; Kenji Kubara; Yohei Mukai; Ryuji Watari; Shinya Sato; Keita Kondo; Shin-Ichi Tsukumo; Koji Yasutomo; Masashi Ito; Kappei Tsukahara

doi:10.1016/j.omtn.2022.09.017

Design and lyophilization of lipid nanoparticles for mRNA vaccine and its robust immune response in mice and nonhuman primates

Mol Ther Nucleic Acids. 2022 Dec 13:30:226-240. doi: 10.1016/j.omtn.2022.09.017. Epub 2022 Sep 24.

Authors

Affiliations

¹ hhc Data Creation Center, Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3 Tokodai, Tsukuba, Ibaraki 300-2635, Japan.
² Drug Discovery Platform, KAN Research Institute, Inc., 6-8-2 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
³ Medicine Development Center, Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3 Tokodai, Tsukuba, Ibaraki 300-2635, Japan.
⁴ Department of Immunology and Parasitology, Graduate School of Medicine, Tokushima University, Tokushima 770-8503, Japan.

Abstract

mRNA and lipid nanoparticles have emerged as powerful systems for the preparation of vaccines against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. The emergence of novel variants or the necessity of cold chain logistics for approved mRNA vaccines undermines the investigation of next-generation systems that could preserve both potency and stability. However, the correlation between lipid nanoparticle composition and activity is not fully explored. Here, we screened a panel of ionizable lipids in vivo and identified lead lipid nanoparticles with a branched-tail lipid structure. Buffer optimization allowed the determination of lyophilization conditions, where lipid nanoparticle-encapsulated mRNA encoding SARS-CoV-2 spike protein could induce robust immunogenicity in mice after 1 month of storage at 5°C and 25°C. Intramuscularly injected lipid nanoparticles distributed in conventional dendritic cells in mouse lymph nodes induced balanced T helper (Th) 1/Th2 responses against SARS-CoV-2 spike protein. In nonhuman primates, two doses of 10 or 100 μg of mRNA induced higher spike-specific binding geometric mean titers than those from a panel of SARS-CoV-2-convalescent human sera. Immunized sera broadly inhibited the viral entry receptor angiotensin-converting enzyme 2 (ACE2) from binding to the spike protein in all six strains tested, including variants of concern. These results could provide useful information for designing next-generation mRNA vaccines.

Keywords: COVID-19; MT: Oligonucleotides: Therapies and Applications; SARS-CoV-2 spike protein; freeze-drying; ionizable lipid; lipid nanoparticles; lyophilization; mRNA; mRNA vaccines; vaccines; viral entry receptor.