Summary
Platelet plasma membranes were found to possess the disaccharide β--galactosyl(1−3)-N-acetyl-D-galactosamine which was measured by gas chromatography after release by alkaline
borohydride treatment and desialylation. Immunological evidence using the specific
lectins from Arachis hypogoea and Agaricus bisporus and an anti-T serum confirmed
the presence of this disaccharide, the immunodominant group of the Thomsen-Friedenreich
antigen (T-antigen). This receptor was only found after prior neuraminidase treatment
indicating that it is normally a cryptic antigen, i.e. masked by sialic acid in the
native membrane. Evidence for a second receptor with terminal N-acetylgalactosamine
was obtained using the lectin from Helix pomatia. The binding of myxovirus and the
lectins from Phaseolus vulgaris (PHA) and Canavalia ensiformis (Con A) to platelet
membrane was also demonstrated.
The implication of the T-antigen in elimination of the platelets and its role in the
haemolytic-uraemic syndrome is discussed.
