Fig. 3.

VFLIP-X elicits cross-neutralizing antibodies against SARS-CoV-2 VOCs and VOIs. BALB/c mice (n = 3) were immunized at weeks 0 and 3 with 1 μg (pink) or 5 μg (red) of circRNA-LNP encoding VFLIP-X. Control mice were administered with PBS (white). (A) Infectious virus 50% neutralization titers (NT50) of seven weeks post-boost sera were determined against the indicated infectious SARS-CoV-2 variant isolates. (B) Lentivirus-based pseudovirus 50% neutralization titers (pVNT50) of seven weeks post-boost sera were determined against the indicated SARS-CoV-2 variants. Data are presented as GMT ± geometric SD. Horizontal dotted lines represent assay limits of detection. Control group was compared with 5 μg immunized group by student's t-test (parametric, two-tailed unpaired). * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001.