Fig. 3.

Antigen-specific antibody responses to VN elicited in BALB/c mice. (A) Adjuvantation effect, (B) anamnestic response. Mice (n = 6) were injected with either two intramuscular doses of SARS-CoV-2 S-protein alone or one intramuscular dose of AlPO₄- or SQ@NP-adjuvanted SARS-CoV-2 S-protein. At Week 12, all mice were boosted i.m. with the same vaccine formulations. Data are presented as GMT with individual mice. The seroconversion rate (SCR) was calculated from the proportion of mice with a minimum 4-fold increase between prevaccination and postvaccination antibody titers. The data are expressed as the individual values plus the GMT. The Log-transformed values of VN titers were compared by performing Student's t-test. *p < 0.05: Comparison with the group of protein alone. ns represents no significant difference.