CD75 Lactosamines
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Carbohydrate
Peripheral blood
Germinal Center
T Cell
Blood Cell
Erythrocyte
B Cell
Epithelial Cell
67 / 67
85 / 85

Expression
CD75, formally was CDw75, is expressed on mature sIg+ B cells, germinal center B cells of the lymphoid secondary follicle with weaker levels on other mature B cells but downregulated on differentiation to plasma cells.  Expression is on a small subpopulation of peripheral blood T cells, erythrocytes, and on a broad range of epithelial cell types and weakly on normal lymphocytes.  The level of expression increases on activation of B cells.



Structure
MOLECULAR FAMILY NAME:  Belongs to the carbohydrate group.

CD75 comprises lactosamine structures.  The carbohydrate epitopes are expressed in association with a variety of glycosphingolipids and on glycoproteins.  CD75 is an ill-defined carbohydrate structure present on N-glycans which contain a2,6-linked sialic acid, NeuAc a2,6 Gal b1,4 GlcNAc core epitope.  Some cells but not all are lacking CD75 expression of the antigen when transfected with the Golgi enzyme b -galactoside a2 ,6-sialyltransferase, EC 2.4.99.1.

MOLECULAR MASS:

The mass is not relevant because it is a carbohydrate epitope.

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION

There is a possible resialylation by ectosialyltransferase.


Ligands
No ligand has been identified. CD75 is not a ligand for the lectin CD22, which binds the sialoglycoconjugate NeuAc a2->6Gal b1->4GlcNAc.

LIGANDS AND MOLECULES ASSOCIATED WITH CD75
Molecule Comment
CD22 Sialoglycan ligand for mediating B-B interactions


Function
BIOCHEMICAL ACTIVITY

CD75 is dependent on a2 ,6 sialyltransferase activity.

DISEASE RELEVANCE AND FUNCTION OF CD75 IN INTACT ANIMAL

CD75 is found on B lymphocytes of patients with carbohydrate deficiency glycoprotein syndrome and differentiates between malignant B cell types.

Comments
MOLECULAR INTERACTIONS -
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD75: Not relevant.

SUBSTRATES: Not relevant.

ENZYMES WHICH MODIFY CD75
Molecule Comment
Neuraminidases with a2,6 activity Cleavage

ADDITIONAL INSIGHTS

Carrier proteins of CD75 sialoglycan epitopes are unknown, but are possibly glycoproteins.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
Antibodies
LN-1   View Reactivity

Revised June 25, 2008


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