Glycolipid studies in small intestine and pancreas of alpha1,3-galactosyltransferase knockout miniature swine: alpha1,3GALT-KO animals lack alphaGAL antigens and contain novel blood group H compounds.
BACKGROUND
To avoid hyperacute rejection of xeno-organs, alpha1,3-galactosyltransferase knock-out (GalT-KO) pigs have been produced. However, Galalpha1,3Gal (Gal) determinant elimination may expose cryptic carbohydrate antigens and/or generate new antigens that might interfere with the human immune response.


METHODS
Glycolipids isolated from small intestine and pancreas of two GalT-KO and one wild-type (WT) pig were tested for immune reactivity with antibodies on thin-layer chromatograms after separation by high-performance liquid chromatography, and selected fractions were analysed by proton NMR spectroscopy.


RESULTS
Immunostaining using purified human anti-Gal Abs revealed that tissues from WT animals express large amounts of Gal-antigens whereas GalT-KO tissues lacked these antigens. Proton NMR spectroscopy on small intestine fractions revealed both linear and branched nona- and decaglycosylceramides, respectively, with terminal Gal-epitopes. In corresponding GalT-KO fractions, Gal-epitopes seemed to be replaced by terminal alpha1,2fucoses. Two novel branched blood group H compounds was found in the GalT-KO intestine.


CONCLUSIONS
The structural complexity of alphaGal-terminating antigens in the WT organs is very high. Knockout of alpha1,3GalT by gene-targeting results in elimination of Gal-determinants. In addition structurally novel alpha1,2fucose-terminated blood group H compounds were identified in the GalT-KO tissue. These compounds are not expected to be recognized by the human immune system.
Diswall
M
M
Department of Surgery, Sahlgrenska University Hospital/campus Ostra, Göteborg, Sweden. mette.diswall@gu.se
Angström
J
J
Schuurman
H-J
HJ
Dor
F J M F
FJ
Rydberg
L
L
Breimer
M E
ME
D000017:ABO Blood-Group System / Q000235:genetics*; D000818:Animals; D000941:Antigens / Q000235:genetics; D005690:Galactose / Q000235:genetics; D005700:Galactosyltransferases / Q000172:deficiency* / Q000235:genetics; D006017:Glycolipids / Q000378:metabolism*; D006801:Humans; D007421:Intestine, Small / Q000201:enzymology / Q000378:metabolism*; D030781:Organisms, Genetically Modified; D010179:Pancreas / Q000378:metabolism*; D013552:Swine / Q000235:genetics; D013556:Swine, Miniature / Q000235:genetics; D014183:Transplantation, Heterologous
D000017:ABO Blood-Group System; D000941:Antigens; D006017:Glycolipids; D005700:Galactosyltransferases; C047006:N-acetyllactosaminide alpha-1,3-galactosyltransferase; D005690:Galactose