Fig. 1. Design overview of V_HH constructs and robust binding of BL1.2 and BL2.2 to a range of native F4 fimbriae and LT expressed by wild-type porcine ETEC strains.

A The VHH constructs used in this study are based on single-domain antibodies derived from camelid heavy chain antibodies, with BL1.2 designed to inhibit F4⁺ ETEC adhesion by blocking its fimbriae, and BL2.2 designed to inhibit excreted LT⁺ toxins. B ELISA showing binding of BL1.2 to F4 fimbriae from different F4⁺ ETEC strains from Danish farms. C ELISA showing binding of BL2.2 to LT toxins in the supernatant of F4⁺LT⁺ ETEC and F18⁺LT⁺ ETEC strains from Danish farms. D Amino acid sequence alignment of LT toxins from porcine (magenta) and human (black) pathogenic ETEC strains.