Studies on the Reversed Passive Latex Agglutination for the Detection of Enterotoxin : Part1. Detection of Cholera Toxin and Heat-Labile Enterotoxin of Escherichia coli

Reversed passive latex agglutination (RPLA) for the detection of cholera toxin (CT) and heat-labile enterotoxin (LT) of Escherichia coli was studied. The assay was based on the immunological similarity between CT and LT. For the sensitization of latex, immunoglobulins against CT were purified by affinity chromatography. A suitable dose of immunoglobulin for sensitization of 0.5% latex suspension was the same amount of 25 μg/ml. It gave detectable agglutination reactions at a concentration of 1 ng/ml of CT. Good correspondence between the results obtaintd by the RPLA test and those by Y_1 adrenal cell assay was observed. The technical procedures of this method is very simple and easy. Also, the results are reliable. The sensitized latex is considered to be stable for at least 1 year when stored at 4℃. Therefore, this method would be recommended for the tests of CT and LT in bacteriology, clinical bacteriology as well as epidemiology of acute enteritis.