The pyrogenicity and immunogenicity of endotoxin are closely related to their chemical structure. Differences in the lenghth and composition of the O-antigen and core oligosaccharide can have significant effects on their biological activity. The number and length of fatty acid chains in the Lipid A portion are also important. Maybe the most dramatic example of how endotoxin structure effects potency is the phosphates on the disaccharide. Mono-phosphoryl endotoxin is completely inert.
A group of scientists in Hungary recently published a new technique which allows fast and quantitative detection of endotoxin species. The technique involves fluorescent labeling of endotoxin followed by electrophoresis on a microchip. The procedure has been used to establish an electrophoretic profile of many bacterial strains. Comparing results to these profiles, the procedure can quickly elucidate bacterial strain with both purified and crude endotoxin samples. This technology provides the ability of, not only, quantitative endotoxin detection but the identification of the source, which may be of equal importance.