Lag-3 (CD223)
Author: Frederic Triebel
Reviewer: Dario A A. Vignali
PROW 3:15-18(2002)

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OVERVIEW Summary Sentence

• The CD223 (LAG-3) product is a 4 Ig-like domain membrane protein expressed only in activated T and NK cells. CD223 associates with MHC class II molecules expressed on monocytes/dendritic cells, which become subsequently activated

Abstract

• CD223 was originally identified in human NK cells as a cDNA that encodes a protein with some distant structural homologies with CD4 . Analysis of the gene structure and its localization to human chromosome 12p13 clearly indicate that CD223 and CD4 have derived from a common ancestor. Indeed, the human and mouse genes are nested between two CD4 enhancer elements, suggesting a controlled expression of these two genes. The CD223 promoter region strictly directs CD223 expression only in T and NK cells following cellular activation. CD223 is a better MHC class II binder than CD4 and needs to be dimerized or oligomerized at the cell surface to stably engage its ligand. On activated T cells, CD223 is present in lipid raft microdomains where it is associated with the CD3/TCR complexes and engagement of CD223 by mAb down-regulates TCR signaling. On the other hand, engagement by CD223 of MHC class II molecules expressed by monocytes or dendritic cells leads to APC activation in vitro and stronger CD8 and CD4 Th1 Ag-specific responses in vivo when a soluble CD223 molecule is used as a vaccine adjuvant

Molecular Families

• Families in which CD223 is a member
  • CD223-->immunoglobulin supergene family

Names

• LAG3 [HUGO gene name]
• lymphocyte activation gene 3 (LAG-3 )
• CD223 (CD223 )

Major Links

• LocusLink: 3902
• Mendelian Inheritance in Man (OMIM): 153337
• SwissProt annotated protein record: P18627

Author's Additional Insights

• The role of CD223/MHC class II interactions in vivo is not clearly established
• These interactions may complement CD40L/CD40 interactions in T/DC cross-talk in conditions where CD40L/CD40 interactions are suboptimal (e.g. lack of CD40L expression on poorly activated CD4 cells or on CD8 cells)

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SYSTEM VIEW Disease Relevance / Function in Vivo

• CD223 knockout mice data have led to propose that CD223 defines a specific mode of natural killing, but no evidence that CD223 may be involved in transducing activity important for NK cell cytotoxicity has been found in human

Cellular Function

• May help to down-regulate TCR signaling, leading to cell inactivation
• May help activated CD4 and CD8 T cells to fully activate monocytes and dendritic cells, leading to optimized MHC class I and class II T cell responses

Protein Location

• Plasma membrane
• May reside in lipid rafts*
• Cocap with the CD3/TCR complexes and the CD8 molecule

Cellular Expression

• Expressed in all subsets of T and NK cells following cellular activation
• Not expressed in other cell types
• The best cytokine combination to induce CD223 is IL-2 + IL-12

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GENE Gene Sequence Links

• GenBank Accession Code: Y13586 [exons 3 to 5], Y10211 [promoter region], Y13537 [3' region]

Chromosomal Location

• 12p13.3 [human]

Gene Polymorphism

• No information

Transcription Regulating Molecules

• No information in table

Gene Annotation

• No information

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TRANSCRIPT Transcript Sequence Links

• GenBank Accession Code: X98113 [mouse], X51985 [human]

Post-transcriptional Modification

• Three alternatively spliced variants described:
  • LAG-3V1 (D1-D2 soluble, 36 kDa)
  • LAG-3V2 (D1-D3 membrane bound, 61 kDa)
  • LAG-3V3 (D1-D3 soluble, 52 kDa)
• Three mRNA with slightly different 5' start sites (spurious transcription)

Transcript Annotation

• No information

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PROTEIN Biochemical Activity

• No information

Protein Sequence Links

• SwissProt annotated protein record: P18627

Protein Sequence Annotation

• One V-type Ig-like domain termed D1
  • The long (about 140 aa) V-type D1 domain binds a nonpolymorphic region of MHC class II and also binds another D1 LAG-3 domain (dimer formation)
  • An unusual 30 aa extraloop in the NH2-terminal D1 Ig domain that is part of the MHC class II binding region
• Two C-type Ig-like domains termed D2 and D3
• One C2-type Ig-like domain termed D4
• Transmembrane and a short intracytoplasmic region with a potential serine phosphorylation site and a repeated EP motif at the COOH terminus, to which binds LAP ("LAG-3-associated protein") an intra-cytoplasmic 45 kDa protein*

Protein Polymorphism

• No information

Protein Physical Properties

Cell_Type	MW_unreduced	MW_reduced	Comment
Activated human T and NK cells	70 kDa	70 kDa
Unknown protein	45 kDa	45 kDa	CD223 is non-covalently associated with a 45 kDa unknown protein

Post-translational Modification

• 4 potential N-glycosylation sites
• Endoglycosydase treatment of the 70 kDa CD223 protein gives a 50 kDa species

Protein Structure Links

• No information

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MOLECULAR INTERACTIONS Molecular Pathways

• No information

Enzymes for which this is a Substrate

• No information in table

Substrates

• No information in table

Other Ligands and Associated Molecules

• No information in table

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REAGENTS Model Animal Strains

Species_or_Strain	Supplier	Comment
LAG-3 knockouts	Dr. Diane Mathis, Boston	{Miyazaki_T/Mathis_D.1996.II} ; {Miyazaki_T/Mathis_D.1996.SCIEN} *

Monoclonal Antibodies

mAb	Supplier	Comment
LAG-3.1-specific mAb (17B4)	{Huard_B/Triebel_F.1994.IMMUN}	IgG1, recognizes the D1 extraloop peptide of human CD223, blocks CD223/MHC class II interactions

Polyclonal Antibodies

• No information in table

Drugs and Small Molecules

• No information in table

Genetic Constructs

• No information in table

Purified Protein

• No information in table

Reagents Misc.

• No information in table

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REFERENCES References

REVIEWS

PRIMARY CITATIONS
1. {Annunziato_F/Romagnani_S.1996.FJ}
Annunziato F, Manetti R, Tomasevic I, Guidizi MG, Biagiotti R, Gianno V, Germano P, Mavilia C, Maggi E, Romagnani S. 1996. Expression and release of LAG-3-encoded protein by human CD4+ T cells are associated with IFN-gamma production . FASEB J 10:769-776
2. {Avice_MN/Demeure_CE.1999.JI}
Avice MN, Sarfati M, Triebel F, Delespesse G, Demeure CE. 1999. Lymphocyte activation gene-3, a MHC class II ligand expressed on activated T cells, stimulates TNF-alpha and IL-12 production by monocytes and dendritic cells. J Immunol 162:2748-2753
3. {Baixeras_E/Piatier-Tonneau_D.1992.JEM}
Baixeras E, Huard B, Miossec C, Jitsukawa S, Martin M, Hercend T, Auffray C, Triebel F, Piatier-Tonneau D. 1992. Characterization of the lymphocyte activation gene 3-encoded protein. A new ligand for human leukocyte antigen class II antigens. J Exp Med 176:327-337
4. {Bruniquel_D/Triebel_F.1997.IMMUN}
Bruniquel D, Borie N, Triebel F. 1997. Genomic organization of the human LAG-3/CD4 locus. Immunogenetics 47:96-98
5. {Bruniquel_D/Triebel_F.1998.IMMUN}
Bruniquel D, Borie N, Hannier S, Triebel F. 1998. Regulation of expression of the human lymphocyte activation gene-3 (LAG-3) molecule, a ligand for MHC class II. Immunogenetics 48:116-124
6. {El_Mir_S/Triebel_F.2000.JI}
El Mir S, Triebel F. 2000. A soluble lymphocyte activation gene-3 molecule used as a vaccine adjuvant elicits greater humoral and cellular immune responses to both particulate and soluble antigens. J Immunol 164:5583-5589
7. {Hannier_S/Triebel_F.1998.JI}
Hannier S, Tournier M, Bismuth G, Triebel F. 1998. CD3/TCR complex-associated lymphocyte activation gene-3 molecules inhibit CD3/TCR signaling. J Immunol 161:4058-4065
8. {Hannier_S/Triebel_F.1999.II}
Hannier S, Triebel F. 1999. The MHC class II ligand lymphocyte activation gene-3 is co-distributed with CD8 and CD3-TCR molecules after their engagement by mAb or peptide-MHC class I complexes. Int Immunol 11:1745-1752
9. {Huard_B/Triebel_F.1994.IMMUN}
Huard B, Gaulard P, Faure F, Hercend T, Triebel F. 1994. Cellular expression and tissue distribution of the human LAG-3-encoded protein, an MHC class II ligand. Immunogenetics 39:213-217
10. {Huard_B/Triebel_F.1995.EJI}
Huard B, Prigent P, Tournier M, Bruniquel D, Triebel F. 1995. CD4/major histocompatibility complex class II interaction analyzed with CD4- and lymphocyte activation gene-3 (LAG-3)-Ig fusion proteins. Eur J Immunol 25:2718-2721
11. {Huard_B/Triebel_F.1996.EJI}
Huard B, Prigent P, Pages F, Bruniquel D, Triebel F. 1996. T cell major histocompatibility complex class II molecules down-regulate CD4+ T cell clone responses following LAG-3 binding. Eur J Immunol 26:1180-1186
12. {Huard_B/Triebel_F.1997.PNASU}
Huard B, Mastrangeli R, Prigent P, Bruniquel D, Donini S, El-Tayar N, Maigret B, Dreano M, Triebel F. 1997. Characterization of the major histocompatibility complex class II binding site on LAG-3 protein. Proc Natl Acad Sci U S A 94:5744-5749
13. {Huard_B/Triebel_F.1998.IL}
Huard B, Tournier M, Triebel F. 1998. LAG-3 does not define a specific mode of natural killing in human. Immunol Lett 61:109-112
14. {Miyazaki_T/Mathis_D.1996.II}
Miyazaki T, Dierich A, Benoist C, Mathis D. 1996. LAG-3 is not responsible for selecting T helper cells in CD4-deficient mice. Int Immunol 8:725-729
15. {Miyazaki_T/Mathis_D.1996.SCIEN}
Miyazaki T, Dierich A, Benoist C, Mathis D. 1996. Independent modes of natural killing distinguished in mice lacking Lag3. Science 272:405-408
16. {Prigent_P/Triebel_F.1999.EJI}
Prigent P, El Mir S, Dreano M, Triebel F. 1999. Lymphocyte activation gene-3 induces tumor regression and antitumor immune responses. Eur J Immunol 29:3867-3876
17. {Triebel_F/Hercend_T.1990.JEM}
Triebel F, Jitsukawa S, Baixeras E, Roman-Roman S, Genevee C, Viegas-Pequignot E, Hercend T. 1990. LAG-3, a novel lymphocyte activation gene closely related to CD4. J Exp Med 171:1393-1405

WWW Resources

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* indicates amended by reviewer, ** indicates added by reviewer
Modified 02/04/02 mpr@mail.nih.gov