Evidence for carbohydrate-deficient forms of the major sialoglycoproteins of human platelets, granulocytes and T lymphocytes in individuals with Tn syndrome.

125I-Helix pomatia and 125I-wheat germ lectins were used as probes to visualise membrane glycoproteins of circulating blood cells from individuals with Tn syndrome. Cells were solubilized in Triton X-100 and subjected to sodium dodecyl sulphate polyacrylamide gel electrophoresis prior to incubation with iodinated lectins. Normal platelets, granulocytes and T lymphocytes have a single major sialoglycoprotein of mol. wt. 143,000, 115,000 and 115,000 respectively. In Tn platelets, granulocytes and T lymphocytes there was a marked reduction in lectin binding in the region of the sialoglycoproteins but new lectin binding components of lower mol. wt. (125,000, 98,000 and 98,000 respectively) were apparent. It is suggested that these new lectin binding components are the sialoglycoproteins with deficient glycosylation resulting from the known deficiency of beta-3-galactosyltransferase in Tn syndrome.