posted on 2021-10-07, 19:43authored byJian Hang Lam, Amit K. Khan, Thomas A. Cornell, Teck Wan Chia, Regine J. Dress, Wen Wang William Yeow, Nur Khairiah Mohd-Ismail, Shrinivas Venkataraman, Kim Tien Ng, Yee-Joo Tan, Danielle E. Anderson, Florent Ginhoux, Madhavan Nallani
Multiple successful vaccines against
severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2) are urgently needed to address the ongoing
coronavirus disease 2019 (Covid-19) pandemic. In the present work,
we describe a subunit vaccine based on the SARS-CoV-2 spike protein
coadministered with CpG adjuvant. To enhance the immunogenicity of
our formulation, both antigen and adjuvant were encapsulated with
our proprietary artificial cell membrane (ACM) polymersome technology.
Structurally, ACM polymersomes are self-assembling nanoscale vesicles
made up of an amphiphilic block copolymer comprising poly(butadiene)-b-poly(ethylene glycol) and a cationic lipid, 1,2-dioleoyl-3-trimethylammonium-propane.
Functionally, ACM polymersomes serve as delivery vehicles that are
efficiently taken up by dendritic cells (DC1 and DC2), which are key
initiators of the adaptive immune response. Two doses of our formulation
elicit robust neutralizing antibody titers in C57BL/6 mice that persist
at least 40 days. Furthermore, we confirm the presence of functional
memory CD4+ and CD8+ T cells that produce T
helper type 1 cytokines. This study is an important step toward the
development of an efficacious vaccine in humans.