Chemical and Immunological Characterization of the Forssman Hapten Isolated from Equine Organs

抄録

Galactosamine-containing glycolipid (Forssman hapten) was isolated from both equine kidney and spleen, by repeated chromatography on silicic acid.
Its chemical composition was identical with that of globoside I (ceramide-glucose-galactose-galactosamine=1:1:2:1 in molar ratio) of human erythrocytes and kidney. The results of methylation of F-hapten followed by gas-chromatographic analyses also indicated a similar structure to that of globoside I.
However, F-hapten could be distinguished from globoside I in its mobility on a thin-layer chromatogram, its optical rotation and its serological specificities.
In serological studies which involved hemolysis- and hemagglutination-inhibition and precipitin reactions, F-hapten isolated from equine kidney and spleen showed human blood group A-activity, in addition to F-activity, while globoside I did not.
The haptens from both equine kidney and spleen were shown to be identical on the bases of their chemical and immunological properties.
The present investigation indicates that the determinant group of F-hapten of the glycosphingoside is most probably O-α-N-acetylgalactosaminoyl-(1→3)-galactose at the non-reducing end, differing from F-inactive globoside I in the anomeric configuration of the disaccharide.
The enhancing effects of various lipids on the F-activity of the hapten were determined by the hemolysis-inhibition test. The results indicated that with an optimal amount of added auxiliary lipid, 0.002-0.018μg. F-hapten/ml. could readily be measured.
The roles of auxiliary lipids and of the lipid moieties in lipid haptens, and the relationship between F-hapten and human blood group-A antigens are discussed.
The authors are indebted to Prof. T. Yamakawa for his kindness in allowing us to continue this research in the present laboratory.
The authors wish to thank Prof. T. Miki and Mrs. Y. Hayashida in Tokyo Medical and Dental University School of Medicine for their guidance in the sheep-red cell hemolysis-inhibition test, for carrying out the human-red cell isoagglutination test, and for gifts of antisera. Thanks are also due to Prof. M. Tomoda of Kyoritsu Pharmaceutical College and Dr. Y. Suzuki of Tohoku University School of Pharma-cology for gifts of authentic samples of 2, 3, 6-tri-O-methylgalactose and egg yolk lecithin, respectively.