Fig. 4

Characterization of the 10 PEDV-S-Nb-HRP fusion proteins expressed in HEK293T cells. A Identification of 10 PEDV-S-Nb-HRP fusion proteins expressed in HEK293T cells by IFA using an anti-HA mAb as the primary antibody and a FITC-labeled goat anti-mouse as the secondary antibody. B The 10 PEDV-S-Nb-HRP fusion proteins in the culture medium of HEK293T cells directly reacting with TMB, as detected by direct ELISA. C The binding of the 10 PEDV-S-Nb-HRP fusion proteins to the PEDV-infected Vero cells, as detected by IFA using the fusion proteins as the primary antibodies. D The 10 PEDV-S-Nb-HRP fusion proteins, with the exception of PEDV-S-Nb86-HRP, had neutralizing activity, as detected by a nanobody neutralization test. E The 10 PEDV-S-Nb-HRP fusion proteins were blocked from binding to PEDV-S by positive pig sera for the anti-PEDV antibody. Significant differences were analyzed with a t test and are marked with asterisks and "ns": ****P < 0.0001; ** P < 0.01