Lymphocyte-activation gene 3 (LAG-3)

The clinical success of several anti-PD1 and anti-CTLA4 antibodies has boosted the research of other immune checkpoint proteins. The lymphocyte-activation gene 3 (LAG-3), is of particular interest to researchers because it functions differently from the canonical negative checkpoint regulators such as PD1 and CTLA4.

LAG-3 is expressed on cell membranes of natural killer cells (NK), B cells, tumor-infiltrating lymphocytes (TIL), T cells, and dendritic cells (DC), and it appears to play complicated roles in the immune pathway. The binding between soluble LAG-3 (sLAG-3) and MHCII molecules promotes the maturation of dendritic cells, while the interaction between MHCII and LAG-3 on membrane leads to the negative regulation of T-cell activity.

Several therapeutic agents have been developed to target the LAG-3 pathway. IMP321, a sLAG-3-Fc fusion protein developed by Prima Biomed, is one of the leading drugs that currently being investigated in a phase II clinical trial. IMP321 augments immune response against cancer cells through two distinct mechanisms. It binds with MHCII molecules on the immature dendritic cells to enhance tumor antigen presentation. At the same time, it also blocks the MHCII molecule to bind with LAG-3-expressing CD8+ T-cells, and by so doing prevents the T-cells from being negatively regulated. Other investigative drugs, such as Bristol-Myers Squibb's anti-LAG-3 antibody BMS-986016, directly bind with LAG-3 expressed on the T-cells and block the LAG-3-MHCII interaction. As a result, the T-cells can be activated to boost immune response.

ACROBiosystems provides a comprehensive panel of LAG-3 proteins, including Cynomolgus LAG-3, Mouse IgG2a Fc Tag (Cat. No. LA3-C52A0), Cynomolgus LAG-3, Fc Tag (Cat. No. LA3-C5252), and Human LAG-3, Fc Tag (Cat. No. LA3-H5255).

LAG-3 Product List

Cat. No.	Species	Product Description	Structure	Purity	Features
LA3-H5222		Human LAG-3 / CD223 Protein, His Tag
LA3-H52Aa		Human LAG-3 / CD223 Protein, Mouse IgG2a Fc Tag
LA3-H5255		Human LAG3 / CD223 Protein, Fc Tag (HPLC-verified)
LA3-H82Fb		Biotinylated Human LAG-3 / CD223 Protein, Fc,Avitag™
LA3-M52H5		Mouse LAG-3 / CD223 Protein, His Tag
LA3-H82F3		Biotinylated Human LAG-3 / CD223 Protein, Mouse IgG2a Fc,Avitag™
LA3-C5252		Cynomolgus LAG-3 / CD223 Protein, Fc Tag
LA3-C52A0		Cynomolgus LAG-3 / CD223 Protein, Mouse IgG2a Fc Tag
LA3-H525c		Human LAG-3 / CD223 Protein, Llama IgG2b Fc Tag, low endotoxin
LA3-H522a		Human LAG-3 / CD223 Protein, His Tag, low endotoxin
LA3-R52H5		Rat LAG3 / CD223 Protein, His Tag
LA3-M52Ha		Marmoset LAG-3 / CD223 Protein, His Tag

Product Highlight

Fig.1 The purity of Human CD73, His Tag (HPLC-verified) (Cat. No. CD3-H52H7) was greater than 90% as determined by SEC-HPLC.

Protocol

FACS analysis of LAG-3 mFc binding to Daudi cell surface

Fig.2 Flow Cytometry assay shows that Human LAG3, Mouse IgG2a Fc Tag (Cat. No. LA3-H52Aa) can bind to Daudi cell surface. The concentration of LAG3 used is 0.3 μg/mL.                    

Protocol

Competitive experiment of neutralizing anti-LAG-3 antibody

Fig.3 FACS analysis shows that the binding Human LAG3, Mouse IgG2a Fc Tag (Cat. No. LA3-H52Aa) to Daudi cells was inhibited by increasing concentration of neutralizing Anti-LAG3 antibody. The concentration of LAG3 used is 1 μg/mL. The IC50 is 0.165 μg/mL.

Protocol

Fig.4 Loaded Anti-LAG-3 mAb (Human IgG1) on AHC Biosensor, can bind Human LAG-3, His Tag (Cat. No. LA3-H5222) with an affinity constant of 7.47 nM as determined in BLI assay (ForteBio Octet Red96e).

Protocol

Fig.5 Immobilized Human LAG-3, Fc Tag (HPLC-verified) (Cat. No. LA3-H5255) at 2 μg/mL (100 μL/well) can bind Madarex LAG-3 mAb with a linear range of 0.4-3 ng/mL. The ELISA date showed that the Human LAG-3 protein has high batch-to-batch consistency.

Protocol

Customer Reviews

References

• Avery et al., 2004, J Clin Invest. 112, 286–297.

• Chiu et al., 2007, Blood 109, 729–739.

• O'Connor et al., 2004, J. Exp. Med. 199, 91–98.

• Peperzak et al., 2013, Nat. Immunol. 14, 290–297.

• Bolkun et al., 2016, J. Cancer 7, 1979–1983.

• Bossen and Schneider, 2006, Semin. Immunol. 18, 263–275.

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