CTLA-4 inhibitor (B7/CD28 interaction inhibitor 1) is a novel and potent inhibitor of CTLA4 or CTLA-4 (cytotoxic T-lymphocyte-associated protein 4). CTLA4 is also known as CD152 (cluster of differentiation 152) and is a protein receptor that, functioning as an immune checkpoint, downregulates immune responses. CTLA4 is constitutively expressed in Tregs but only upregulated in conventional T cells after activation. It acts as an 'off' switch when bound to CD80 or CD86 on the surface of antigen-presenting cells. Polymorphisms of the CTLA-4 gene are associated with autoimmune diseases such as autoimmune thyroid disease and multiple sclerosis, though this association is often weak. In Systemic Lupus Erythematosus (SLE), the splice variant sCTLA-4 is found to be aberrantly produced and found in the serum of patients with active SLE.

Physicochemical Properties

Molecular Formula	C21H13F4N5O
Molecular Weight	427.36
Exact Mass	427.105
CAS #	635324-72-0
Related CAS #	635324-72-0
PubChem CID	101136468
Appearance	Off-white to light yellow solid powder
Density	1.5±0.1 g/cm3
Boiling Point	599.5±60.0 °C at 760 mmHg
Flash Point	316.4±32.9 °C
Vapour Pressure	0.0±1.7 mmHg at 25°C
Index of Refraction	1.677
LogP	3.8
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	8
Rotatable Bond Count	2
Heavy Atom Count	31
Complexity	685
Defined Atom Stereocenter Count	0
InChi Key	WQKVVTLTCHDAST-UHFFFAOYSA-N
InChi Code	InChI=1S/C21H13F4N5O/c1-29-19-15(10-26-29)18-16(20(31)30(28-18)14-7-5-13(22)6-8-14)17(27-19)11-3-2-4-12(9-11)21(23,24)25/h2-10,28H,1H3
Chemical Name	2-(4-Fluoro-phenyl)-6-methyl-4-(3-trifluoromethyl-phenyl)-1,6-dihydro-2H-1,2,5,6,7-pentaaza-as-indacen-3-one
Synonyms	CTLA-4 inhibitor;CTLA4 inhibitor;CTLA 4 inhibitor
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro

To create an exceptionally stable signaling complex, the divalent B7.1 homodimer is bridged by the divalent CTLA4 homodimer. Immunosuppression and improved allograft survival are the outcomes of blocking B7/CD28 interaction with soluble receptors or monoclonal antibodies, while B7/CTLA-4 blockage strengthens anticancer immune responses. An essential part of naive T cell activation involves the interaction between B7 molecules on antigen-presenting cells and costimulatory molecules on T cells. Drugs that interfere with these interactions might therefore be helpful in the management of autoimmune disorders and transplant rejection [1].

References

[1]. Structure-activity studies of a series of dipyrazolo[3,4-b:3',4'-d]pyridin-3-ones binding to the immune regulatory protein B7.1. Bioorg Med Chem. 2003 Jul 3;11(13):2991-3013.

Solubility Data

Solubility (In Vitro)

DMSO: 10 mM Water:N/A Ethanol:N/A

Solubility (In Vivo)

Solubility in Formulation 1: 2.08 mg/mL (4.87 mM) in 10% DMSO + 40% PEG300 +5% Tween-80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 + to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.3399 mL	11.6997 mL	23.3995 mL
	5 mM	0.4680 mL	2.3399 mL	4.6799 mL
	10 mM	0.2340 mL	1.1700 mL	2.3399 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.