Abstract
By the enzyme-labeled antibody method, Escherichia coli was examined for cellular localization of O antigen. Peroxidase was conjugated with γ-globulin which had been isolated from anti-O rabbit serum. Coupling was accomplished, by using p, p'-difluoro m, m'-dinitrophenylsulfone (FNPS).
Conjugated antibody reacted with Escherichia coli cells or cell wall preparation. The electron microscope was used for observation of the reaction. Electron density increased in places unequally and mosaic-like in the three most external layers of the cell wall. This observation is interesting, since Petris has suggested that lipopolysaccharide may make mosaic with lipoprotein in the cell wall of Escherichia coli. When the conjugate reacted with heterogeneous Escherichia coli cells, there was no increase in electron density. The peroxidase-labeled antibody method seems to be excellent, as it has a high specificity and conjugate penetrates tissues more easily than ferritin.
In addition, the ferritin-labeled antibody method, the cell fractionation method, and the Ouchterlony method were used to observe the cellular localization of O antigen.
Endotoxin was extracted by the phenol-water method or with trichloracetic acid. When observed by electron microscopy, endotoxin showed a variety of shape and had an extremely large myelin-like structure. The section of endotoxin appeared as three layers, and had some similarities to the outer surface of the whole cell.
