(A) SDS-PAGE of Nb-3G2, Nb-4D11 and Nb-3F9. (B) Standard curves of ic-ELISA based on Nb-3G2, Nb-4D11, and Nb-3F9. (C) SDS-PAGE of Nb-3F9-Nluc, (D) Evaluation of nanoluciferase catalytic activity, nanobody binding activity, and specific TeA inhibition activity of Nb-3F9-Nluc. The nanoluciferase catalytic activity of Nb-3F9-Nluc was determined in the presence or absence of bioluminescent substrate CTZ-h, the nanobody binding activity of Nb-3F9-Nluc was determined in the presence or absence of coating antigen by direct noncompetitive BLEIA, and the specific TeA inhibition activity of Nb-3F9-Nluc was determined in the presence or absence of TeA by direct competitive BLEIA.