Constitutively hyposialylated human T-lymphocyte clones in the Tn-syndrome: binding characteristics of plant and animal lectins.

Abstract

Previously, beta 1,3-galactosyltransferase-deficient (Tn+) and normal (TF+) T-lymphocyte clones have been established from a patient suffering from Tn-syndrome [Thurnher et al. (1992) Eur J Immunol 22: 1835-42]. Tn+ T lymphocytes express only Tn antigen GalNAc alpha 1-O-R) while other O-glycan structures such as sialosyl-Tn (Neu5Ac alpha 2,6GalNAc alpha 1-O-R) or TF (Gal beta 1-3GalNAc alpha 1-O-R) antigens are absent from these cells as shown by flow cytometry using specific mABs for TF and sialosyl-Tn antigen, respectively. Normal T lymphocytes express the TF antigen and derivatives thereof. The surface glycans of Tn+ and TF+ cells were then analysed by flow cytometry using the following sialic acid-binding lectins: Amaranthus caudatus (ACA), Maackia amurensis (MAA), Limax flavus (LFA), Sambucus nigra (SNA) and Triticum vulgare (WGA). Equal and weak binding of MAA and SNA to both TF+ and Tn+ cells was found. WGA, LFA and ACA bound more strongly to TF+ cells than to Tn+ cells. Binding of ACA to TF+ cells was enhanced after sialidase treatment. To investigate the possible biological consequences of hyposialylation, binding of three sialic acid-dependent adhesion molecules to Tn+ and TF+ cells was estimated using radiolabelled Fc-chimeras of sialoadhesin (Sn), myelin-associated glycoprotein (MAG) and CD22. Equal and strong binding of human CD22 to both TF+ and Tn+ cells was found. Whereas binding of Sn and MAG to TF+ cells was strong (100%), binding to Tn+ cells amounted only to 33% (Sn) and 19% (MAG). These results indicate that the in vivo interactions of T lymphocytes in the Tn syndrome with CD22 are not likely to be affected, whereas adhesion mediated by Sn or MAG could be strongly reduced.

• Authors: K Mrkoci, S Kelm, P R Crocker, R Schauer, E G Berger
• Journal: Glycoconjugate journal (Glycoconj J) Vol. 13 Issue 4 Pg. 567-73 (Aug 1996) ISSN: 0282-0080 [Print] United States
• PMID: 8872113 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens, Tumor-Associated, Carbohydrate
• Lectins
• Plant Lectins
• Tn antigen
• N-Acetylneuraminic Acid

Topics

• Animals
• Antigens, Tumor-Associated, Carbohydrate (blood)
• Carbohydrate Sequence
• Clone Cells
• Hematologic Diseases (blood)
• Humans
• Lectins (metabolism)
• Molecular Sequence Data
• N-Acetylneuraminic Acid (metabolism)
• Plant Lectins
• Plants (metabolism)
• Protein Binding
• Syndrome
• T-Lymphocytes (metabolism)