• Species Reactivity

  Human

• Specificity

  Detects human LAG-3 in direct ELISAs and Western blots. In direct ELISAs and Western blots, less than 1% cross-reactivity with recombinant mouse LAG-3 is observed.

• Source

  Polyclonal Goat IgG

• Purification

  Antigen Affinity-purified

• Immunogen

  Mouse myeloma cell line NS0-derived recombinant human LAG-3    
  Leu23-Leu450    
  Accession # P18627

• Formulation

  Supplied in a saline solution containing BSA and Sodium Azide.

• Label

  Fluorescein

Applications

• 
  

  Recommended    
  Concentration

  Sample

• Flow Cytometry

  10 µL/10    ⁶ cells

  See below

• 
  

Please Note: Optimal dilutions should be determined by each laboratory for each application.  are available in the Technical Information section on our website.

Data Examples

Preparation and Storage

• Shipping

  The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.

• Stability & Storage

  Protect from light.    Do not freeze.    

• 12 months from date of receipt, 2 to 8 °C as supplied.

Background: LAG-3

LAG-3 (Lymphocyte activation gene-3), also known as CD223, is a member of the immunoglobulin superfamily (IgSF). The mature LAG-3 protein is a 496 amino acid (aa) membrane protein with a 421 aa extracellular region which contains four IgSF domains, a 21 aa transmembrane region and a 54 aa cytoplasmic region. LAG-3 and CD4 molecules share < 20% aa sequence homology but have a similar structure (1, 2). Both molecules bind to MHC class II. LAG-3 binds to MHC class II with higher affinity compared to CD4. Both LAG-3 and CD4 genes are located on the distal part of the short arm of chromosome 12.

LAG-3 is an activation-induced molecule, expressed on activated T cells and NK cells, but not on resting T cells. Studies using LAG-3 ^-/- mice have shown significant delay of T cell apoptosis following antigen stimulation and increased size of memory T cells pool following infection (3, 4). It also has been reported that anti-LAG-3 antibodies up-regulate T cell activation by blocking interaction of LAG-3 and MHC class II. The study has demonstrated that LAG-3 is selectively expressed on activated CD4⁺CD25⁺ T_Reg cells and plays a role in their suppressive activity (5). This evidence indicated, unlike the interaction of CD4 with MHC class II that plays a positive role in T cell activation, LAG-3 binds to MHC class II and negatively regulates T cell activation through LAG-3 signaling. On the other hand, studies have shown that binding of LAG-3 to MHC class II molecules on antigen presenting cells induce maturation of dendritic cells and cytokine secretion by monocytes through MHC class II signal transduction (6). Taken together, LAG-3 may have two major functions, it negatively regulates T cells activation through LAG-3 signaling and stimulates antigen presenting cells which express MHC class II.

• References:

1. Triebel, F. et al. (1990) J. Exp. Med. 171:1393.

2. Baixeras, E. et al. (1992) J. Exp. Med 176:327.

3. Workman, C.J. and D.A. Vignali (2003) Eur. J. Immunol. 33:970.

4. Workman, C.J. et al. (2004) J. Immunol. 172:5450.

5. Huang, C.T. et al. (2004) Immunity 21:503.

6. Andreae, S. et al. (2003) Blood 102:2130.

• Long Name:

  Lymphocyte-activation Gene 3

• Entrez Gene IDs:

  3902 (Human); 16768 (Mouse); 297596 (Rat); 102122272 (Cynomolgus Monkey)

• Alternate Names:

  CD223 antigen; CD223; FDC; LAG3; LAG-3; lymphocyte activation gene 3 protein; lymphocyte-activation gene 3; Protein FDC