What Are Immune Checkpoint Proteins?

As described in the question- What is an immune checkpoint? Immune checkpoints are regulators of the immune system. These immune checkpoints are crucial for self-tolerance, which prevents the immune system from attacking cells indiscriminately. Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Immune checkpoint proteins refer to a series of proteins coded by the gene of immune checkpoints.

Immunological checkpoint proteins play an important role in the field of cancer immunotherapy research, which is a series of molecules that produce co-stimulatory or inhibitory signals in immune responses. Cancer cells escape the immune system by weakening the immune response by making the immune checkpoint signal abnormal. Therefore, it is an important way to treat cancer by strengthening the immune response by agonists of co-stimulatory signals or antagonists of co-suppression signals to kill cancer cells. CUSABIO's R&D team has developed about 50 immune checkpoint related proteins. Please click here to view all of immune checkpoints.

Over more than 11 years, CUSABIO Protein Expression Platform has established five recombinant expression systems from prokaryotic to eukaryotic, and has also built unique in vitro E. coli expression system, which enables us to express transmembrane proteins that are usually quite difficult to express. The quality of our proteins is the cornerstone of our ability to serve our clients. For this reason, we invest tremendous resources in developing proteins, validating their application, controlling and improving quality. Each protein will undergo our standardized quality control process before shipped, which include concentration detection, purity detection, endotoxin removal, activity detection, et al. In addition to strict quality control, there are some reasons to choose CUSABIO's proteins.

There are several active immune checkpoint proteins confirmed by our strict quality control. As the Table 1 shows:

Table 1. The active immune checkpoint proteins from CUSABIO

Product Name	Code	Uniprot ID	Source
Recombinant Human CD160 antigen(CD160)	CSB-AP005221HU	O95971	Mammalian cell
Recombinant Human Tumor necrosis factor receptor superfamily member 5(CD40),partial	CSB-AP005171HU	P25942	Mammalian cell
Recombinant Human Tumor necrosis factor receptor superfamily member 5(CD40),partial	CSB-AP005181HU	P25942	Mammalian cell
Recombinant Human CD40 ligand(CD40LG),partial	CSB-AP005191HU	P29965	E.coli
Recombinant Human Leukocyte surface antigen CD47(CD47),partial	CSB-AP005201HU	Q08722	Mammalian cell
Recombinant Human Leukocyte surface antigen CD47(CD47),partial	CSB-AP005211HU	Q08722	Mammalian cell
Recombinant Mouse Leukocyte surface antigen CD47(Cd47),partial	CSB-AP005351MO	Q61735-2	Mammalian cell
Recombinant Human T-lymphocyte activation antigen CD86(CD86),partial	CSB-AP005161HU	P42081	Mammalian cell
Recombinant Guinea pig Cytotoxic T-lymphocyte associated protein 4(CTLA4),partial	CSB-AP005121GU	H0VUB1	Yeast
Recombinant Human Cytotoxic T-lymphocyte protein 4(CTLA4),partial	CSB-AP005231HU	P16410	Mammalian cell
Recombinant Mouse Cytotoxic T-lymphocyte protein 4(Ctla4),partial	CSB-AP005301MO	P09793	Mammalian cell
Recombinant Human Hepatitis A virus cellular receptor 2(HAVCR2),partial	CSB-AP005281HU	Q8TDQ0	Mammalian cell
Recombinant Human Hepatitis A virus cellular receptor 2(HAVCR2),partial	CSB-AP005291HU	Q8TDQ0	Mammalian cell
Recombinant Mouse Hepatitis A virus cellular receptor 2 homolog(Havcr2),partial	CSB-AP005341MO	Q8VIM0	Mammalian cell
Recombinant Human Tyrosine-protein phosphatase non-receptor type substrate 1(SIRPA),partial	CSB-AP005271HU	P78324	Mammalian cell
Recombinant Mouse Tumor necrosis factor receptor superfamily member 14(Tnfrsf14),partial	CSB-AP005311MO	Q80WM9	Mammalian cell
Recombinant Human Tumor necrosis factor receptor superfamily member 4(TNFRSF4),partial	CSB-AP005241HU	P43489	Mammalian cell
Recombinant Human Tumor necrosis factor receptor superfamily member 4(TNFRSF4),partial	CSB-AP005251HU	P43489	Mammalian cell
Recombinant Mouse Tumor necrosis factor receptor superfamily member 4(Tnfrsf4),partial	CSB-AP005321MO	P47741	Mammalian cell
Recombinant Mouse Tumor necrosis factor receptor superfamily member 4(Tnfrsf4),partial	CSB-AP005331MO	P47741	Mammalian cell
Recombinant Human Tumor necrosis factor receptor superfamily member 9(TNFRSF9),partial	CSB-AP005131HU	Q07011	Mammalian cell
Recombinant Human Tumor necrosis factor receptor superfamily member 9(TNFRSF9),partial	CSB-AP005141HU	Q07011	Mammalian cell
Recombinant Human Tumor necrosis factor receptor superfamily member 9(TNFRSF9),partial	CSB-AP005151HU	Q07011	Mammalian cell
Recombinant Human Tumor necrosis factor ligand superfamily member 4(TNFSF4),partial	CSB-AP005261HU	P23510	Mammalian cell

Partial active immune checkpoint proteins activity verification

The ED50 as determined by its ability to bind Mouse B7-1 in functional ELISA is less than 0.4 ug/ml. (Code: CSB-AP005121GU)

The ED50 as determined by its ability to bind Human TNFSF9 in functional ELISA is less than 50 ug/ml. (Code: CSB-AP005141HU)

The ED50 as determined by its ability to bind Human SIRPA in functional ELISA is less than 20 ug/ml. (Code: CSB-AP005201HU)