[Enterotoxin-like factor(s) produced by Vibrio parahaemolyticus]

Culture filtrates obtained from several isolates of Vibrio parahaemolyticus were tested for their enterotoxin-like activities. Also their antigenic relationship with cholera enterotoxin and Kanagawa hemolysin were tested. In the Chinese Hamster Ovary (CHO) cells assay which are usually employed for detecting cholera toxin or heat labile enterotoxin produced by enterotoxigenic Escherichia coli, crude culture filtrates obtained from both Kanagawa positive and negative strains isolated from patients showed positive reaction whereas most of the Kanagawa negative strains isolated from environmental sources did not. After concentration, however, both the culture filtrates of Kanagawa positive and negative strains of Vibrio parahaemolyticus showed positive reactions in CHO cell assay and rabbit skin permeability assay but not in rabbit ileal loop test. Antisera against concentrated culture filtrates obtained from both Kanagawa positive and negative strains neutralized neutralized the activities of concentrated culture filtrates in CHO cell assay and Rabbit permeability assay but not of cholera toxin and Kanagawa hemolysin. Immunodiffusion test was also carried out using the antisera and the concentrated culture filtrates obtained from both of Kanagawa positive and negative strains of Vibrio parahaemolyticus. The antisera cross-reacted with all concentrated culture filtrates obtained from both Kanagawa positive and negative strains but not reacted with cholera toxin and Kanagawa hemolysin. These results indicated that both of Kanagawa positive and negative strains of Vibrio parahaemolyticus can produce the enterotoxin-like factor(s) such as cholera enterotoxin or heat labile enterotoxin produced by enterotoxigenic Escherichia coli, but this factor(s) dose not show cross-antigenicity with cholera enterotoxin and the Kanagawa hemolysin produced by Kanagawa positive Vibrio parahaemolyticus.