COM503 

COM503 is a high-affinity anti-IL18BP human monoclonal antibody with a K_d value of 0.291 pM. COM503 binds to IL18BP, blocks the IL18BP:IL18 interaction, displaces IL18 from preformed complexes, and enhances the activation and function of T cells and NK cells. COM503 induces anti-tumor effects by relieving the activity inhibition of endogenous IL18 in the tumor microenvironment. COM503 can be used for cancer research. The recommended isotype control is Human IgG4 (S228P) kappa, Isotype Control (HY-P99003)^[1].

Human IgG4 kappa

Human IgG4 (S228P) kappa, Isotype Control

Human

COM503 binds to purified human IL18BP with high affinity (K_d = 0.291 pM), which is higher than the affinity between endogenous human IL18 and IL18BP (K_d = 0.441 pM)^[1].
COM503 (1.25-10 μg/mL; 1 h (complex incubation at 37°C); RT or 37°C (assay incubation steps)) displaces IL18 from preformed recombinant human IL18:IL18BP complexes in a dose-dependent manner in vitro, with an EC₅₀ of 14 nM^[1].
COM503 (24 h) restores the activation of human melanoma CD8⁺ tumor-infiltrating lymphocytes (TILs) co-cultured with MEL624 cells and mediated by IL18, and increases the secretion levels of IFN-γ and TNF-α as well as the expression of CD137 in CD8⁺ TILs^[1].
COM503 (24 h) restores IL18-mediated activation of isolated human NK cells blocked by preformed IL18:IL18BP complexes, and increases IFN-γ secretion levels^[1].
COM503 (10 μg/mL; 24 h) restores IL18-mediated activation of CMV-reactive CD8⁺ T cells co-cultured with PD-L1-overexpressing MEL624 cells^[1].
COM503 (24 h) restores IL18-mediated activation of human peripheral blood mononuclear cells (PBMCs) by blocking endogenously secreted IL18BP, and increases IFN-γ secretion levels with a mean EC₅₀ of 1.6 nM^[1].
COM503 (20 μg/mL; 24 h) enhances IFN-γ secretion by human melanoma CD8⁺ tumor-infiltrating lymphocytes (TILs) co-cultured with MEL624 cells through blocking endogenously secreted IL18BP at physiologically relevant IL18 concentrations^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

10068  [NCBI]

O95998

IL-18BP

ELISA, FACS, Functional assay

Unconjugated

The product can be reconstituted/diluted with sterile PBS or saline.

Please refer to the lot-specific COA for specific buffer information.

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Menachem A, et al. Unleashing Natural IL18 Activity Using an Anti-IL18BP Blocker Induces Potent Immune Stimulation and Antitumor Effects. Cancer Immunol Res. 2024;12(6):687-703.