CD7 Leu 9, 3A1, gp40, T cell leukemia antigen
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Lineage Restricted Molecule
Type 1 glycoprotein
T Cell
Hematopoietic Cell
Thymocyte
Peripheral blood
Bone Marrow
NK Cell
Leukemia cell
Stem Cell
Liver
Thymus
Lymphoid Cell
Myeloid Cell
40 / 40

Expression
CD7 is the earliest marker antigen expressed in the T lineage, being found on T cell precursors in fetal liver and thorax prior to thymic colonization and in thymus and bone marrow. CD7 is expressed on most human thymocytes, a major subset of peripheral blood T cells, mature T cells, NK cells, pluripotential hematopoietic stem cells, and progenitor cells of lymphoid and myeloid cells.  CD7 is a marker for pluripotential stem cell leukemias and T cell acute lymphocytic leukemia.

Structure
MOLECULAR FAMILY NAME: Belongs to the immunoglobulin supergene family.

CD7 is a single-pass type-1 glycoprotein.  It contains an extracellular domain which contains a N-terminal Ig-like V-type domain followed by a putative O-glycosylated extended "stalk" which is separated from the transmembrane sequence by 4 consensus repeats containing a high proportion of Pro, Ser and Thr residues.  The extended stalk is like that proposed for the CD8 hinge.  The gene for CD7 is similar to the murine Thy-1 gene which places it in a class of tissue-specific genes whose promoters lack a TATA element.

MOLECULAR MASS
Cell Type Unreduced Reducted
T cell lymphoma 40 kDa

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION

The extracellular region contains 2 potential N-linked glycosylation sites. 

Ligands
No ligand for the extracellular region of CD7 has been identified. On crosslinking with mAb, CD7 associates with PI 3-kinase possibly through a YXXM motif in the cytoplasmic domain.

LIGANDS AND MOLECULES ASSOCIATED WITH CD7
Molecule Comment
Phosphartidylinositol 3-kinase (PI-3 kinase) Cross-linking of the receptor with mAb, CD7 associates with phosphatidylinositol 3-kinase (PI-3 kinase) by a YEDM motif in the cytoplasmic region


Function
Cross-linking studies with mAbs suggest that CD7 can function as a co-stimulatory molecule after T cell activation, induce cytokine secretion and modify cellular adhesion.  CD7 plays an essential role in T cell interactions and also in T cell/B cell interaction during early lymphoid development indicating an important role in regulatory T cell and NK-T cell ontogeny and prevention of autoimmune disease.    A proposal that CD7 is an IgM receptor has not been confirmed in expression studies using the mDNA clone.  CD7 mAbs co-stimulate T cell proliferation and induce 2nd messengers.  Soluble recombinant CD7 has been reported to inhibit antigen-specific T cell proliferation in a mixed lymphocyte reaction.  A CD7 deficient mouse might give clues on the physiological function of CD7 in the development of T cells and other leukocyte lineages.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD7 IN INTACT ANIMAL

Studies have implicated CD7 as a co-activation molecule that modulates cytokine secretion and adhesion of cells treated mAb.  A CD7 deficient patient with severe combined immunodeficiency (SCID) has been described.  CD7 is a clinical marker for T cell acute lymphocyte leukemia. ALL), pluripotential stem cell leukemia, acute myleoid leukemia (ALL) and myelodysplasia.  It is also a potential therapeutic target in the treatment of rheumatoid arthritis and may be a useful target for immunosuppression in transplant patients

Comments
MOLECULAR INTERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD7: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD7: No information.



Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 924P09564
MouseP50283D10329
Antibodies
3A1E-12H7   View Reactivity
8H8.1   View Reactivity
CBC.37   View Reactivity
LT7   View Reactivity
M-T701   View Reactivity
YTH30.15   View Reactivity

Revised June 25, 2008


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