Table 1. ELISA assay of different A. hydrophila whole cells and polyclonal O34-antigen antiserum from A. hydrophila AH-3, adsorbed with the rough AH-3ΔwaaL mutant [20].

Strain and main characteristics	A405 (means ±SD) a
AH-3	1.9 ± 0.12
AH-405; AH-3 rifampicin-resistant mutant	1.7 ± 0.2
AH-3Δ wecP	< 0.2
AH-3Δ wecP+ pBAD33	< 0.2
AH-3Δ wecP + pBAD-WecPAh	1.7 ± 0.10
AH-3Δ wecP + pBAD33-WecAEc	0.7 ± 0.09
AH-3Δ wecP + pBAD-WecA-WzyEEc	1.6 ± 0.13
AH-3Δ wecP + pBAD-WzyEEc	< 0.2

^a The values are the averages of three independent experiments.

The strains carrying pBAD plasmids were grown under inducing conditions (+ arabinose)