|
|
|
|
|
|
|
||
Brief Definitive Reports |
Department of Biochemistry, University of Dundee, Dundee DD1 5EH, United Kingdom; and the Electron Microscopy Unit, Nuffield Department of Pathology, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
CD22 is a B cell–specific transmembrane protein known to function as a negative regulator of B cell signaling. It has also been implicated in cell adhesion through recognition of
2,6-linked sialic acids on glycans of target cells. Previous studies showed that CD22-deficient mice had a strongly reduced population of mature recirculating B cells in the bone marrow despite normal B cell development. Using a soluble recombinant form of the receptor (CD22-Fc), we demonstrate here that sialylated ligands for CD22 are expressed on sinusoidal endothelial cells of murine bone marrow but not on endothelial cells in other tissues examined. Injection of CD22-Fc revealed that the CD22 ligands in the bone marrow were accessible to the circulation. Treatment of mice with either CD22-Fc or affinity-purified anti-CD22 antibody led to an 
50% reduction in mature recirculating B cells in the bone marrow without affecting numbers in the spleen. Finally, consistent with the notion that CD22 is a homing receptor, we show that compared with wild-type mice, CD22-deficient animals have a lower number of immunoglobulin M–secreting plasma cells in the bone marrow.
Key Words: lymphocyte homing • B cells • sialic acid binding • siglec • CD22
L. Nitschke and H. Floyd contributed equally to this work.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Facebook 
Reddit 
Technorati 
Twitter What's this?
| TABLE OF CONTENTS |
|
