Fig. 1: Adjuvanted Spike vaccine protected against SARS-CoV-2 lethal challenge and elicited neutralizing antibody response.
From: Development of COVID-19 vaccine using a dual Toll-like receptor ligand liposome adjuvant
K18-hACE2 mice (n = 10 per group) were immunized on days 0, 14, and 28 with adjuvanted full-length spike protein using a combination of subcutaneous (SC, days 0 and 28) and intranasal (IN, day 14) routes. Mice were challenged with SARS-CoV-2 two weeks after the final immunization. a Survival analysis: Nine out of ten control mice succumbed to infection by day-6 postchallenge. All the vaccinated mice survived until the termination of the experiment (day-18). b Anti-S1 IgG: Prechallenge plasma was collected a week after final immunization and anti-S1 IgG levels were measured by ELISA. c Pseudovirus entry neutralization. Prechallenge plasma obtained a week post-third immunization was evaluated to assess the ability to inhibit pseudovirus entry in Vero E6 cells. Plasma from immunized mice (Vac-1 to Vac-3) showed neutralization capability equivalent to human convalescent plasma (conv. plasma). Boxes denote mean with standard deviation. Asterisk indicates that the results are statistically significant as follows: ***p < 0.001.
