CD80  B7-1, BB1, Ly-53
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 1 glycoprotein
Monocyte
Peripheral blood
Dendritic Cell
B Cell
T Cell
Langerhans Cell
Macrophage
60 / 60

Expression
CD80 is expressed on activated B and T cells, macrophages and dendritic cells.  Expression is increased upon activation of peripheral blood monocytes and with the culture of  Langerhans cells.  Signaling through the MHC class II cytoplasmic domain may induce CD80 expression on B cells.


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

CD80 is a single-pass type-1 glycoprotein.  It contains a signal peptide, an extracellular region which contains 1 Ig-like V-type domain and 1 Ig-like C2-type Ig domain, both  of which are highly glycosylated and has 8 N-linked glycosylation sites, a hydrophobic transmembrane domain and a variable short cytoplasmic domain ranging from a 16 aa-31 aa depending on the species and the splice variant.  In mice, a splice variant has been identified which lacks the C2-set domain.  CD80 is structurally related to CD86 with a  25% identity.  The sequence of the transmembrane domain is unusual in containing 3 cysteine residues, 2 of which are also present in CD86.  The short cytoplasmic domain, which bears no similarity to the CD86 cytoplasmic domain, has a preponderance 9/19 of arginine residues and contains a potential site for calmodulin-dependent phosphorylation, RRES.

MOLECULAR MASS
Cell Type Unreduced Reduced Comment
B cells 60 kDa (immunoprecipitation) Highly glycosylated so broad MW

POST-TRANSCRIPTIONAL MODIFICATION

Alternative splicing yields 2 different isoforms which encode the cytoplasmic domain.

POST-TRANSLATIONAL MODIFICATION

CD80 has 8 N-linked glycosylation sites.

Ligands
CD80 binds to CD28 and CD152 (CTLA-4) using the same site on the GFCC'C'' b sheet of the V-set domain, through the C2-set domain which may also contribute to binding.  CD80 binds CD152 with a slightly higher affinity than CD28 of kDa 0.4 and 4 mM, respectively with both interactions having fast dissociation rate constants of K off >0.4 and >1.6 s-1, respectively.

LIGANDS AND MOLECULES ASSOCIATED WITH CD80
Molecule Comment
CD28 Activation of T cells
CD152 (CTLA4) Inhibits T cell activation

 

Function
CD80 is a B lymphocyte activation antigen which  provides regulatory signals for T lymphocytes through the binding of CD28 and CD152.  The interaction of CD80 or CD86 with CD28 provides a potent co-stimulatory signal for T cell proliferation functions and activation through the CD3 complex.  CD80 binding to CD28 results in T cell activation whereas binding to CD152 provides inhibitory signals to T cells.  CD80 is expressed later than CD86 and appears to be less important in the primary immune response.  Mice deficient in CD80 are less severely affected than CD86-deficient mice and have nearly normal TH1 and TH2 responses. 

BIOCHEMICAL ACITIVITY OF CD80: No information.

DISEASE RELEVANCE OF CD80 AND FUNCTION OF CD80 IN INTACT ANIMAL

A distinct signaling event is induced by CD80 and CD86 molecules in B cell lymphoma.  CD80 is involved in the allo-activation of T cells.  A critical role of CD80 exists in autoimmune, humoral and transplant responses.  The CD28-CD80 complex is a potential therapeutic target in the treatment of rheumatoid arthritis.

Comments
MOLECULAR INTERACTIONS -
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD80: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD80: No information.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 941P33681
MouseS17291Q00609X60958
RatU05593
Antibodies
2D10.4   View Reactivity
BB1   View Reactivity
L307.4   View Reactivity
MAB104   View Reactivity
MEM-233   View Reactivity

Revised June 25, 2008


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