Identification and characterization of the murine homologue of CD22, a B lymphocyte-restricted adhesion molecule
| Autor: | R M, Torres, C L, Law, L, Santos-Argumedo, P A, Kirkham, K, Grabstein, R M, Parkhouse, E A, Clark |
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| Rok vydání: | 1992 |
| Předmět: |
B-Lymphocytes
Mice Inbred BALB C Base Sequence Sialic Acid Binding Ig-like Lectin 2 T-Lymphocytes Molecular Sequence Data Sialyltransferases Antigens Differentiation B-Lymphocyte Mice Antigens CD Cricetinae Lectins Cell Adhesion Animals Humans Amino Acid Sequence RNA Messenger Cell Adhesion Molecules beta-D-Galactoside alpha 2-6-Sialyltransferase Cells Cultured Conserved Sequence |
| Zdroj: | Journal of immunology (Baltimore, Md. : 1950). 149(8) |
| ISSN: | 0022-1767 |
| Popis: | The human B lymphocyte-specific Ag, CD22, is a cell adhesion molecule expressed on the surface during a narrow window of B cell development, coincident with surface IgD. A ligand for CD22 has recently been identified on human T cells as the low molecular mass isoform of the leukocyte common Ag, CD45RO. CD22 has been reported to function in the regulation of both T and B cell activation in vitro. In this study, we report the isolation and expression of a molecular cDNA clone encoding the murine homologue of CD22, mCD22. Within their predicted protein sequences, murine and human sequences overall have 62% identity, which includes 18 of 20 extracellular cysteines and six of six cytoplasmic tyrosines. BHK cells transfected with mCD22 cDNA specifically adhere to resting and activated T lymphocytes and in addition bound activated, but not resting, B cells. Five Th clones were analyzed for their ability to adhere to mCD22; two Th0 clones and one Th1 clone bound CD22+ BHK transfectants, but not all T cell clones bound CD22+ cells: another Th1 clone and a Th2 clone did not. mCD22+ BHK transfectants were also specifically bound by the B cell-specific mAb, NIM-R6, demonstrating that this mAb is specific for murine CD22. Human cell lines expressing the counter-receptors for human CD22 were also examined for adhesion to the murine CD22 homologue; the epitope responsible for B cell adhesion to CD22 is conserved, whereas the T cell epitope binding to CD22 is not. The cDNA and mAb to murine CD22 will be useful for defining the in vivo function of CD22. |
| Databáze: | OpenAIRE |
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