CD73: A novel target for immunotherapy

CD73 is known as ecto-5-prime-nucleotidase, the enzyme consists of a dimer of 2 identical 70-kD subunits bound by a glycosyl phosphatidyl inositol (GPI) linkage to the external face of the plasma membrane. The enzyme is used as a marker of lymphocyte differentiation. CD73 works with its upstream signaling molecule CD39 to convert extracellular ATP to adenosine. Adenosine in tumor microenvironment can help regulatory T cells suppress and shut down immune activity. Tumor cells can also express CD73 which can promote the release of adenosine, thereby reducing antitumor activity.

An article^[1] published in Nature Medicine identified CD73 as a specific immunotherapeutic target to improve antitumor immune responses to immune checkpoint therapy in glioblastoma multiforme. The researchers pointed out that anti-CD73 antibodies have achieved good results in preclinical and early clinical studies, and proposed a strategy for CD73, PD-1 and CTLA-4 blocking combined therapy for glioblastoma.

ACROBiosystems provides CD73 proteins with high enzyme activity, which can help expedite your anti-CD73 mAb drug development. The high purity and bioactivity of these CD73 proteins have been verified by HPLC, BLI, SPR and ELISA. Protocols are provided for free.

Enzyme Activity

Measured by its ability to hydrolyze the 5’-phosphate group from the substrate adenosine-5’-monophosphate (AMP). The specific activity is > 37,000 pmol/min/μg.

Purity

The purity of CD73 proteins are verified by SEC-HPLC.

SEC-HPLC

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

Bioactivity

The bioactivity of CD73 proteins are verified by BLI, SPR and ELISA, and the protocols are offered.

BLI

Fig.2 Loaded Anti-CD73 MAb (Human IgG1) on AHC Biosensor, can bind Human CD73, His Tag (Cat. No.CD3-H52H7) with an affinity constant of 0.179 nM as determined in BLI assay (ForteBio Octet Red96e).

Protocol

SPR

Fig.3 Anti-CD73 antibody (Human IgG1) captured on CM5 chip via anti-human IgG Fc antibodies surface can bind Human CD73, His Tag, HEK293 (Cat. No. CD3-H52H7) with an affinity constant of 0.164 nM as determined in SPR assay (Biacore 8K).

Protocol

ELISA

Fig.4 Immobilized Human CD73, His Tag (HPLC-verified) (Cat. No. CD3-H52H7) at 2 μg/mL (100 μL/well) can bind Monoclonal Anti-Human CD73 Antibody, Human IgG1 with a linear range of 0.15-5 ng/mL.

Protocol