Ligation of tumour-produced mucins to CD22 dramatically impairs splenic marginal zone B-cells

Biochem J. 2009 Feb 1;417(3):673-83. doi: 10.1042/BJ20081241.


CD22 [Siglec-2 (sialic acid-binding, immunoglobulin-like lectin-2)], a negative regulator of B-cell signalling, binds to alpha2,6- sialic acid-linked glycoconjugates, including a sialyl-Tn antigen that is one of the typical tumour-associated carbohydrate antigens expressed on various mucins. Many epithelial tumours secrete mucins into tissues and/or the bloodstream. Mouse mammary adenocarcinoma cells, TA3-Ha, produce a mucin named epiglycanin, but a subline of them, TA3-St, does not. Epiglycanin binds to CD22 and inhibits B-cell signalling in vitro. The in vivo effect of mucins in the tumour-bearing state was investigated using these cell lines. It should be noted that splenic MZ (marginal zone) B-cells were dramatically reduced in the mice bearing TA3-Ha cells but not in those bearing TA3-St cells, this being consistent with the finding that the thymus-independent response was reduced in these mice. When the mucins were administered to normal mice, a portion of them was detected in the splenic MZ associated with the MZ B-cells. Furthermore, administration of mucins to normal mice clearly reduced the splenic MZ B-cells, similar to tumour-bearing mice. These results indicate that mucins in the bloodstream interacted with CD22, which led to impairment of the splenic MZ B-cells in the tumour-bearing state.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / immunology
  • Adenocarcinoma / metabolism*
  • Animals
  • Antigens, T-Independent / immunology
  • Antigens, T-Independent / metabolism
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / metabolism
  • Binding Sites
  • CHO Cells
  • Cell Line, Tumor
  • Cricetinae
  • Cricetulus
  • Female
  • Membrane Glycoproteins / metabolism
  • Mice
  • Mice, Inbred Strains
  • Mucins / metabolism*
  • Receptors, Antigen, B-Cell / metabolism
  • Sialic Acid Binding Ig-like Lectin 2 / immunology
  • Sialic Acid Binding Ig-like Lectin 2 / metabolism*
  • Signal Transduction
  • Spleen / immunology*


  • Antigens, T-Independent
  • Membrane Glycoproteins
  • Mucins
  • Receptors, Antigen, B-Cell
  • Sialic Acid Binding Ig-like Lectin 2
  • epiglycanin protein, mouse