nanobodies interact with native outer membrane proteins. Serial tenfold dilutions of the nanobodies were used in ELISA to assess the binding with linear or conformational epitopes. OMPs (1 µg/mL) were coated in a 96-well plate and the interaction of His-tagged nanobodies with native, untreated OMP, and with denatured protein extract was measured. Binding of A Nb5, B Nb22, C Nb23, D Nb24, E Nb49 and F Nb84 was measured. For detection, mouse anti-Histidine tag monoclonal antibody and goat anti-mouse IgG conjugated to alkaline phosphatase were used. The error bars represent the standard deviations.