Immunization with EDIII-Fc protects mice from ZIKV challenge.

A. Timeline for mice immunization with EDIII-Fc and blood collection. Balb/c mice were immunized with EDIII-Fc or PBS. Pre-immune blood samples were obtained 2 days before immunization, and subsequent samples were collected weekly post-immunization. B. Changes of total antibody levels in mice after immunization. Serum samples from mice immunized with EDIII-Fc (in red) or PBS (in black) were serially diluted at a 1:10 ratio. HRP-labeled sheep anti-mouse monoclonal antibody was used for ELISA detection. C. Detection of neutralizing antibody levels in mice. Two weeks after the second immunization, the sera to be tested were serially diluted 2-fold in PBS, starting from a 1:5 ratio, for plaque reduction neutralization testing. Results are reported as the fold dilution of serum that inhibited 50% of plaque formation. D. Serum viral load in mice after challenge. One week after the second immunization, seven Balb/c mice were injected subcutaneously with 10⁴ PFU of ZIKV. Daily blood samples were collected and qPCR was carried out for viral load detection. Three replications were done in each experiment, and the experiment was repeated three times. *: P < 0.05;****: P < 0.0001. Clipart image from https://openclipart.org/.