ABSTRACT
A self-transcribing and replicating RNA (STARR™) based vaccine (LUNAR®-COV19) has been developed to prevent SARS-CoV-2 infection. The vaccine encodes an alphavirus-based replicon and the SARS-CoV-2 full length spike glycoprotein. Translation of the replicon produces a replicase complex that amplifies and prolong SARS-CoV-2 spike glycoprotein expression. A single prime vaccination in mice led to robust antibody responses, with neutralizing antibody titers increasing up to day 60. Activation of cell mediated immunity produced a strong viral antigen specific CD8+ T lymphocyte response. Assaying for intracellular cytokine staining for IFN-γ and IL-4 positive CD4+ T helper lymphocytes as well as anti-spike glycoprotein IgG2a/IgG1 ratios supported a strong Th1 dominant immune response. Finally, single LUNAR-COV19 vaccination at both 2 μg and 10 μg doses completely protected human ACE2 transgenic mice from both mortality and even measurable infection following wild-type SARS-CoV-2 challenge. Our findings collectively suggest the potential of Lunar-COV19 as a single dose vaccine.
Competing Interest Statement
Daiki Matsuda, Elizabeth Allen, Paula Hartma3, Jenny Park, Maher Alayyoubi, Hari Bhaskaran, Adrian Dukanovic, Belle Bao, Brenda Clemente, Jerel Vega, Scott Roberts, Jose A. Gonzalez, Marciano Sablad, Rodrigo Yelin, Wendy Taylor, Kiyoshi Tachikawa, Suezanne Parker, Priya Karmali, Jared Davis, Sean M. Sullivan, Steve G. Hughes, Pad Chivukula are salaried employees of Arcturus Therapeutics, Inc. San Diego CA
