Studies on glycolipid antigens in small intestine and pancreas from alpha1,3-galactosyltransferase knockout miniature swine.
BACKGROUND
To avoid hyperacute rejection of xeno-organs, alpha1,3-galactosyltransferase knockout (GalT-KO) pigs have been produced. Galalpha1,3Gal determinant elimination may expose cryptic carbohydrate antigens and/or generate new antigens. This is the first biochemical study of carbohydrate antigens in GalT-KO pig organs.


METHODS
Neutral and acidic glycolipids were isolated from small intestine and pancreas of two GalT-KO and one wild-type (WT) pig. Glycolipid immune reactivity was tested on thin-layer chromatograms. Small intestine neutral glycolipids were separated by high-performance liquid chromatography and selected fractions were analyzed by proton nuclear magnetic resonance spectroscopy. Total gangliosides were quantified on thin-layer chromatograms and in microtiter wells.


RESULTS
Using Galalpha1,3nLc4 glycolipid reference, total Galalpha1,3Gal glycolipid antigens in the WT animal was estimated at about 30 microg (small intestine) and 3 microg (pancreas) per gram of dry tissue. Galalpha1,3Gal determinants were not detected in GalT-KO tissues at a detection limit of less than 0.25% (small intestine) and 0.5% (pancreas) of the WT tissues. Isoglobotriaosylceramide (iGb3) was absent but trace amounts of Fuc-iGb3 was found in both GalT-KO and WT pig small intestine. Blood group H type 2 core saccharide compounds were increased in GalT-KO pancreas. Total amount of gangliosides was decreased in GalT-KO tissues. The alpha1,3-galactosyltransferase acceptor, N-acetyllactosamine determinant, was not increased in GalT-KO tissues. Human serum antibodies reacted with WT organ Galalpha1,3Gal antigens and gangliosides, of which the ganglioside reactivity remained in GalT-KO tissues.


CONCLUSIONS
Knockout of porcine alpha1,3-galactosyltransferase gene results in elimination of Galalpha1,3Gal-terminated glycolipid compounds. GalT-KO genetic modification did not produce new compensatory glycolipid compounds reactive with human serum antibodies.
Department of Surgery, Sahlgrenska University Hospital/Campus Ostra, Göteborg, Sweden.
Mette
M
Diswall
Jonas
J
Angström
Henk-Jan
HJ
Schuurman
Frank J M F
FJ
Dor
Lennart
L
Rydberg
Michael E
ME
Breimer
D000818:Animals; D030801:Animals, Genetically Modified; D000906:Antibodies / Q000097:blood; D000941:Antigens / Q000032:analysis*; D005700:Galactosyltransferases / Q000172:deficiency* / Q000235:genetics; D006017:Glycolipids / Q000032:analysis* / Q000276:immunology; D006801:Humans; D007421:Intestine, Small / Q000276:immunology*; D010179:Pancreas / Q000276:immunology*; D013552:Swine; D013556:Swine, Miniature
D000906:Antibodies; D000941:Antigens; D006017:Glycolipids; D005700:Galactosyltransferases; C047006:N-acetyllactosaminide alpha-1,3-galactosyltransferase