New, sensitive rocket immunoelectrophoretic assay for measurement of the reaction between endotoxin and Limulus amoebocyte lysate

Abstract

To study the active proteins which participate in the reaction of Limulus amoebocyte lysate (LAL) with lipolysaccharide [Escherichia coli], antibody was raised in rabbits against LAL. When LAL was run against rabbit antiserum in crossed immunoelectrophoresis, a complex precipitin pattern appeared. Profound changes took place after reaction of LAL with lipopolysaccharide. The most distinct change was the complete disappearance of the cathodic migrating protein coagulogen, because the antigenicity of coagulogen was lost. Based on this observation, a new rocket immunoelectrophoretic method was developed to detect the disappearance of coagulogen after reaction of LAL with lipopolysaccharide. This assay method was used on clinical specimens (CSF, plasma, ascites and urine). It was qualitative when a single sample was tested or quantitative when a number of sample dilutions were tested. The new method showed a higher degree of accuracy and sensitivity in comparison with the tube test; it can be used for research and diagnosis.