Immunochemical Investigations on Neisseria Gonorrhoeae Endotoxin

Phenol‐water extracted endotoxin from three strains of Neisseria gonorrhoeae were composed mainly of carbohydrate and lipid and contained much less protein than aqueous ether extracted endotoxin from the same strain. All phenol‐water preparations contained glucose, galactose, glucosamine and heptose, i. e. the same sugars as those found in aqueous ether preparations. In addition, 2‐keto‐3‐deoxy‐octulosonic acid (KDO) was demonstrated in the phenol‐water preparations. Haemagglutination‐inhibition showed that, like aqueous ether preparations, all phenol‐water extracted endotoxins contained an antigenic determinant probably of polysaccharide nature (determinant a ). With respect to this determinant, they tended to exhibit a higher degree of serological activity than the corresponding aqueous ether preparations. An antigenic determinant probably of protein nature (determinant b ) found in aqueous ether preparations from all three strains was present in phenol‐water preparations from only two of the three gonococcal strains.