Human LAG-3 Antibody

Catalog #: MAB23197 Datasheet / COA / SDS

Catalog #	Availability	Size / Price	Qty
MAB23197-100
MAB23197-SP

Detection of LAG-3 in HEK293 Human Cell Line Transfected with Human LAG-3 and eGFP by Flow Cytometry.

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Human LAG-3 Antibody Summary

Species Reactivity

Human

Specificity

Detects human LAG-3 in direct ELISA.

Source

Monoclonal Mouse IgG_2B Clone # 874528

Purification

Protein A or G purified from hybridoma culture supernatant

Immunogen

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

Formulation

Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose. *Small pack size (SP) is supplied either lyophilized or as a 0.2 µm filtered solution in PBS.

Label

Unconjugated

Applications

Recommended Concentration

Sample

Flow Cytometry

0.25 µg/10⁶ cells

See below

Immunohistochemistry

8-25 µg/mL

Immersion fixed paraffin-embedded sections of mouse spleen

CyTOF-ready

Ready to be labeled using established conjugation methods. No BSA or other carrier proteins that could interfere with conjugation.

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

Scientific Data

Flow Cytometry

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Detection of LAG-3 in HEK293 Human Cell Line Transfected with Human LAG-3 and eGFP by Flow Cytometry. HEK293 human embryonic kidney cell line transfected with either (A) human LAG-3 or (B) irrelevant transfectants and eGFP was stained with Mouse Anti-Human LAG-3 Monoclonal Antibody (Catalog # MAB23197) followed by APC-conjugated Anti-Mouse IgG Secondary Antibody (Catalog # F0101B). Quadrant markers were set based on control antibody staining (Catalog # MAB0041, data not shown). View our protocol for Staining Membrane-associated Proteins.

Immunohistochemistry

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LAG‑3 in Mouse Spleen. LAG‑3 was detected in immersion fixed paraffin-embedded sections of mouse spleen using Mouse Anti-Human LAG‑3 Monoclonal Antibody (Catalog # MAB23197) at 15 µg/mL for 1 hour at room temperature followed by incubation with the Anti-Mouse IgG VisUCyte™ HRP Polymer Antibody (VC001). Before incubation with the primary antibody, tissue was subjected to heat-induced epitope retrieval using Antigen Retrieval Reagent-Basic (CTS013). Tissue was stained using DAB (brown) and counterstained with hematoxylin (blue). Specific staining was localized to lymphocytes. Staining was performed using our protocol for IHC Staining with VisUCyte HRP Polymer Detection Reagents.

Reconstitution Calculator

Preparation and Storage

Reconstitution

Reconstitute at 0.5 mg/mL in sterile PBS.

Shipping

Lyophilized product is shipped at ambient temperature. Liquid small pack size (-SP) is shipped with polar packs. Upon receipt, store immediately at the temperature recommended below.

Stability & Storage

Use a manual defrost freezer and avoid repeated freeze-thaw cycles.

12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
6 months, -20 to -70 °C under sterile conditions after reconstitution.

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

Triebel, F. et al. (1990) J. Exp. Med. 171:1393.
Baixeras, E. et al. (1992) J. Exp. Med 176:327.
Workman, C.J. and D.A. Vignali (2003) Eur. J. Immunol. 33:970.
Workman, C.J. et al. (2004) J. Immunol. 172:5450.
Huang, C.T. et al. (2004) Immunity 21:503.
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; LAG3; LAG-3; lymphocyte activating 3; lymphocyte activation gene 3 protein; lymphocyte-activation gene 3; Secreted lymphocyte activation gene 3 protein; sLAG-3