Interaction between Aeromonas veronii and epithelial cells of spotted sandbass (Paralabrax maculatofasciatus) in culture

An in vitro fish model to study the interaction between Aeromonas veronii a nd skin, gill and intestinal epithelial cells was developed using primary c ultures of mucosal cells (isolated from healthy organisms). Primary culture s were exposed to Aeromonas veronii strain A186 isolated from a patient wit h severe gastrointestinal disease. Microbial adherence was assessed by a sp ectrophotometric evaluation of an enzyme-linked, biotin-streptavidin Aer. v eronii cell-adhesion assay to confluent monolayers of epithelial cells on 9 6-well tissue culture plates. The three primary-culture cells are susceptib le to Aer. veronii attachment, with the greatest binding affinity found in gills, and to a lesser extent, in skin and intestine epithelial. cells. Aer . veronii adherence was dependent on bacterial load and incubation time. Th e effect of glycoconjugates on Aer. veronii adhesion was investigated by pr e-incubating Aer. veronii cells with monosaccharides, sialic acid-rich glyc oproteins and sulphated polysaccharides. In addition, the participation of a 48-kDa Aer. veronii lectin (MCBP - mucosal constituents binding protein), with affinity for mucosal constituents, was evaluated as a putative adhesi on factor of Aer. veronii to the mucosal epithelial cells of spotted sand b ass by pre-incubating bacterial cells with rabbit polyclonal antibodies to Aer. veronii MCBP. Our study shows that primary-culture fish mucosal cells provide a suitable model for the study of the interactions between Aer. ver onii and epithelial cells of the fish mucosa, and to study putative virulen ce factors of fish pathogens.