Novel glycolipid variations revealed by monoclonal antibody immunochemical analysis of weak ABO subgroups of A.
OBJECTIVE
The chemical basis of the subgroups of A is largely unknown. We used thin-layer chromatography immunochemical staining techniques together with a range of characterized monoclonal reagents to analyse glycolipids isolated from a variety of weak subgroups.


METHODS
Glycolipids isolated from red cells collected from nine genetically defined individuals of the rare subgroups of A, including a novel A(3) allele (A(2) 539G>A) not described previously, were subjected to a highly sensitive thin-layer chromatographic immunochemical analysis.


RESULTS
Semicharacterized monoclonal antibodies revealed that, in addition to the expected quantitative differences between common phenotypes and the weak subgroups, qualitative glycolipid differences (or at least an apparent qualitative basis), caused by major changes in the ratios of different structures exist. Specifically it was found that the weakest A-expressing samples (A(el) phenotype) appeared to express an unusual A structure in the 8-12 sugar region. Variable expression of several structures in one of the A weak samples were suggestive of novel blood group A structures.


CONCLUSIONS
Although no structural characterization could be undertaken, the results are clearly indicative that the variant glycosyltransferases of the rare ABO subgroups are not only inefficient, but they may potentially synthesize novel ABO structures.
Svensson
L
L
Blood Centre, Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.
Rydberg
L
L
Hellberg
A
A
Gilliver
L G
LG
Olsson
M L
ML
Henry
S M
SM
D000017:ABO Blood-Group System / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D000911:Antibodies, Monoclonal; D002855:Chromatography, Thin Layer; D005838:Genotype; D006017:Glycolipids / Q000032:analysis* / Q000737:chemistry; D016695:Glycosyltransferases; D006801:Humans; D007124:Immunoenzyme Techniques; D007983:Lewis Blood Group Antigens; D010641:Phenotype
D000017:ABO Blood-Group System; D000911:Antibodies, Monoclonal; D006017:Glycolipids; D007983:Lewis Blood Group Antigens; D016695:Glycosyltransferases