Fig. 2: Monovalent circRNA vaccine induces antibody response in mice.

a Five mice per group were immunized with two doses of monovalent circRNA vaccine (N1, N2, IBV) at a four-week interval. Sera were collected 3 weeks after both the prime and boost immunization. A blank LNP group was used as a control. The figure was created by the author using Adobe Illustrator 2020. Binding antibodies against Mich15 (b), SL32 (c), and BCOL17 (d) NA recombinant proteins were detected by ELISA. ELISA was performed to assess the binding ability of N1 monovalent (e), N2 monovalent (f), IBV monovalent (g) circRNA immune sera to heterologous N1, N2, IBV NA recombinant protein. The radar diagram shows the geometric mean titer (GMT) of each group (n = 5). The abbreviation of the virus strain was the same as in Fig. S1. NAI antibodies against Mich15 (h), SL32 (i), and BCOL17 (j) were detected by ELLA. Using recombinant protein as antigen. Neutralization titers of boost immune sera against CA09 (k), SL32 (l), and BCOL17 (m) virus were detected by microneutralization assay. Data are presented as the mean ± SD (n = 5), and each symbol represents one animal. The dashed lines correspond to the lowest initial dilution. Statistical significance was performed by One-way ANOVA; Unpaired Student’s t tests were used to compare antibody titers between prime and boost sera within the same dosage group of mice; *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; ns, not significant.