Differential expression of alpha2-6 sialylated polylactosamine structures by human B and T cells

Glycobiology. 1999 Apr;9(4):399-406. doi: 10.1093/glycob/9.4.399.

Abstract

We found that human peripheral B and T cells differed in the surface expression of alpha2-6 sialylated type 2 chain glycans. In contrast to B cells, T cells expressed only sialoglycans with repeated N-acetyllactosamine (Galss1-4GlcNAc) disaccharides. This finding was based on the specificity of the monoclonal antibodies HB6, HB9 (CD24), HD66 (CDw76), FB21, and CRIS4 (CDw76) with the alpha2-6 sialylated model gangliosides IV6NeuAcnLc4Cer (2-6 SPG), VI6NeuAcnLc6Cer (2-6 SnHC), VIII6NeuAcnLc8Cer (2-6 SnOC), and X6NeuAcnLc10Cer (2-6 SnDC). We found that, in addition to their common requirement of an alpha2-6 bound terminal sialic acid for binding, the antibodies displayed preferences for the length of the carbohydrate backbones. Some of them bound mainly to 2-6 SPG with one N-acetyllactosamine (LacNAc) unit (HB9, HD66); others preferentially to 2-6 SnHC and 2-6 SnOC, with two and three LacNAc units, respectively (HB6 and FB21); and one of them exclusively to very polar alpha2-6 sialylated type 2 chain antigens (CRIS4) such as to 2-6 SnOC and even more polar gangliosides with three and more LacNAc units. These specificities could be correlated with the cellular binding of the antibodies as follows: whereas all antibodies bound to human CD 19 positive peripheral B cells, their reactivity with CD3 positive T cells was either nearly lacking (HD66, HB9), intermediate (about 65%: HB6, FB21) or strongly positive (CRIS4, 95%). Thus, the binding of the antibodies to 2-6 sialylated glycans with multiple lactosamine units appeared to determine their binding to T-cells.

Publication types

  • Comparative Study

MeSH terms

  • Amino Sugars / chemistry*
  • Amino Sugars / immunology
  • Amino Sugars / metabolism*
  • Antibodies, Monoclonal
  • Antigens, Surface / chemistry
  • B-Lymphocytes / immunology
  • B-Lymphocytes / metabolism*
  • Carbohydrate Sequence
  • Glycolipids / chemistry
  • Glycolipids / immunology
  • Glycolipids / metabolism
  • Humans
  • Molecular Sequence Data
  • Polysaccharides / chemistry*
  • Polysaccharides / immunology
  • Polysaccharides / metabolism*
  • Sialic Acids / chemistry
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism*

Substances

  • Amino Sugars
  • Antibodies, Monoclonal
  • Antigens, Surface
  • Glycolipids
  • Polysaccharides
  • Sialic Acids
  • polylactosamine