International Immunology, Vol. 15, No. 10, pp. 1137-1147,
October 2003
© 2003 Japanese Society for Immunology
FEATURED ARTICLE OF THE MONTH |
Transitional and marginal zone B cells have a high proportion of unmasked CD22: implications for BCR signaling
1 Institute of Virology and Immunobiology, University of Würzburg, Versbacherstrasse 7, 97078 Würzburg, Germany 2 Department of Molecular Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92075, USA 3 Present address: Novartis Pharma, Lichtstrasse 35, 4056 Basel, Switzerland
Correspondence to: L. Nitschke; E-mail: nitschke{at}vim.uni-wuerzburg.de
Transmitting editor: S. Izui
CD22, a B cell-specific member of the Siglec family, is an important inhibitor of B cell signaling. The first Ig-like domain of CD22 specifically binds to 
2,6-linked sialic acids. Through these interactions CD22 can mediate adhesion to other cells in trans, but can also bind endogenous ligands on the B cell surface in cis. Cis binding of CD22 to sialylated ligands enhances the efficiency of inhibition and thereby reduces the BCR signaling strength. In this study we used a newly developed oligomeric streptavidin-based sialylated probe as an artificial CD22 ligand. We found that CD22 is bound to ligands in cis on most B cells. However, there is a proportion of B cells with unbound (unmasked) CD22. The subpopulation with unmasked CD22 is 2-fold increased in transitional and marginal zone B cells in the spleen and on B1 cells in the peritoneum, when compared to mature B cells. Also, B cells with unmasked CD22 have an activated phenotype. Unmasking of CD22 could be functionally involved in lowering the signaling threshold on developmental checkpoints such as transitional B cells and during B cell activation or could be a consequence of such activation processes.
Keywords: B lymphocyte, CD22, sialic acid, Siglec
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  M. Rakhmanov, B. Keller, S. Gutenberger, C. Foerster, M. Hoenig, G. Driessen, M. van der Burg, J. J. van Dongen, E. Wiech, M. Visentini, et al. Circulating CD21low B cells in common variable immunodeficiency resemble tissue homing, innate-like B cells PNAS, August 11, 2009; 106(32): 13451 - 13456. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. H. Courtney, E. B. Puffer, J. K. Pontrello, Z.-Q. Yang, and L. L. Kiessling Sialylated multivalent antigens engage CD22 in trans and inhibit B cell activation PNAS, February 24, 2009; 106(8): 2500 - 2505. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. M. Haas, S. Sen, I. G. Sanford, A. S. Miller, J. C. Poe, and T. F. Tedder CD22 Ligand Binding Regulates Normal and Malignant B Lymphocyte Survival In Vivo. J. Immunol., September 1, 2006; 177(5): 3063 - 3073. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. K. Grewal, M. Boton, K. Ramirez, B. E. Collins, A. Saito, R. S. Green, K. Ohtsubo, D. Chui, and J. D. Marth ST6Gal-I Restrains CD22-Dependent Antigen Receptor Endocytosis and Shp-1 Recruitment in Normal and Pathogenic Immune Signaling. Mol. Cell. Biol., July 1, 2006; 26(13): 4970 - 4981. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Ghosh, C. Bandulet, and L. Nitschke Regulation of B cell development and B cell signalling by CD22 and its ligands {alpha}2,6-linked sialic acids Int. Immunol., April 1, 2006; 18(4): 603 - 611. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Varki and T. Angata Siglecs--the major subfamily of I-type lectins Glycobiology, January 1, 2006; 16(1): 1R - 27R. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Nitschke, F. Lajaunias, T. Moll, L. Ho, E. Martinez-Soria, S. Kikuchi, M.-L. Santiago-Raber, C. Dix, R. M. E. Parkhouse, and S. Izui Expression of aberrant forms of CD22 on B lymphocytes in Cd22a lupus-prone mice affects ligand binding Int. Immunol., January 1, 2006; 18(1): 59 - 68. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Robertson, J. Wu, J. Arends, C. Zhou, J. McMahon, L. Torres, and Y.-H. Lou Activation of Glomerular Basement Membrane-Specific B Cells in the Renal Draining Lymph Node after T Cell-Mediated Glomerular Injury J. Am. Soc. Nephrol., November 1, 2005; 16(11): 3256 - 3263. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. E. Collins, O. Blixt, A. R. DeSieno, N. Bovin, J. D. Marth, and J. C. Paulson Masking of CD22 by cis ligands does not prevent redistribution of CD22 to sites of cell contact PNAS, April 20, 2004; 101(16): 6104 - 6109. [Abstract] [Full Text] [PDF]
|
|