Fig. 2.

Mice immunized with VFLIP-X full length spike produce neutralizing antibodies against B.1.1.529. BALB/c mice (n = 3) were immunized at weeks 0 and 3 with 5 μg of circRNA-LNP encoding HexaPro-X (blue) or VFLIP-X (red). Control mice were administered with PBS (white). (A) IgG levels of two weeks post-boost sera were assessed by enzyme-linked immunosorbent assay (ELISA) using recombinant Omicron (B.1.1.529) spike protein. (B) Neutralization activity of two weeks post-boost sera were determined using B.1.1.529 pseudotyped virus. Data are presented as GMT ± geometric SD. Horizontal dotted lines represent assay limits of detection. Immunized groups were compared by student's t-test (parametric, two-tailed unpaired). ** p < 0.01.