Abstract: The aim of this study was to develop a rapid method for the detection of Flavobacterium columnaris based on a double antibody sandwich ELISA （DAS-ELISA）. Purified monoclonal antibody against Flavobacterium columnaris was used as the capture antibody, while polyclonal antibody was used as the detection antibody. The optimal conditions for the ELISA were as follows: monoclonal antibody with 0.08 μg per well was added to coat overnight at 4 ℃; the plate was blocked by 30 g/L bovin serum albumin for 90 min at 37 ℃; incubation concentration of polyclonal antibody was 0.11 μg per well; the incubation time for detection antigen, polyclonal antibody and enzyme labeled antibody was 1 h at 37 ℃ for each; the value of D_{492 nm} was obtained after 15 min coloration. Judging with P/N≥2.1 and D_{492 nm}≥0.776 as positive criteria. This method had no cross reaction with Edwardsiella tarda, E. coli, Aeromonas hydrophila, Vibrio anguillarum, Vibrio alginolyticus, Vibrio parahaemolyticus and Vibrio harveyi. Its minimum detectable limit was 1×10³ CFU. Therefore, this study provided a specific and sensitive detection method for Flavobacterium columnaris for the first time.  

Key words: Flavobacterium columnaris; double antibody sandwich ELISA; monoclonal antibody