Recombinant Human CST7 protein(Met1-His145), hFc-tagged

• Cat.No.: CST7-679H
• Product Overview: Recombinant Human CST7 (NP_003641.3) (Met 1-His 145) was expressed in HEK293 with the fused Fc region of Human IgG1 at the C-terminus.

Specification

• Species: Human
• Source: HEK293
• Tag: Fc
• Protein Length: 1-145 a.a.
• Form: Lyophilized from sterile PBS, pH7. 4. Normally 5 % - 8 % trehalose, mannitol and 0.01% Tween80 are added as protectants before lyophilization.
• Bio-activity: Measured by its ability to inhibit active Cathepsin L cleavage of a fluorogenic peptide substrate Z-LR-AMC. The IC50 value is <5 nM.
• Molecular Mass: The recombinant human Cystatin-F/Fc is a disulfide-linked homodimeric protein. The reduced monomer consists of 364 amino acids and predicts a molecular mass of 41.3 kDa. As a result of glycosylation, the rh Cystatin-F/Fc monomer migrates as an approximately 50 kDa band in SDS-PAGE under reducing conditions.
• Endotoxin: < 1.0 EU per μg of the protein as determined by the LAL method
• Purity: > 97 % as determined by SDS-PAGE
• Storage: Samples are stable for up to twelve months from date of receipt at -20°C to -80°C. Store it under sterile conditions at -20°C to -80°C. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.
• Reconstitution: It is recommended that sterile water be added to the vial to prepare a stock solution of 0.2 ug/ul. Centrifuge the vial at 4°C before opening to recover the entire contents.

Gene Information

• Gene Name: CST7 cystatin F (leukocystatin) [ Homo sapiens ]
• Official Symbol: CST7
• Synonyms: CST7; cystatin F (leukocystatin); cystatin-F; cystatin-7; leukocystatin; cystatin-like metastasis-associated protein; CMAP
• Gene ID: 8530
• mRNA Refseq: NM_003650
• Protein Refseq: NP_003641
• MIM: 603253
• UniProt ID: O76096

Case Study

Case 1: Senjor E, et al. Cell Mol Life Sci. 2023

Cystatin F, a cysteine protease inhibitor, regulates NK cell cytotoxicity via N-glycosylation. High-mannose glycosylation in NK-92 cells drives lysosomal retention, suppressing cathepsin C and cytotoxicity, while complex glycosylation in super-charged NKs promotes secretory pathways, preserving tumor-killing potential. Kifunensine-induced high-mannose glycans reduced cytotoxicity (p<0.01), whereas mannose-6-phosphate blocked cystatin F uptake. Glycosylation modulation enhances NK cell therapy efficacy for cancer immunotherapy.

Fig1. Western blot of cystatin F (CSTF) and cathepsin C (CatC) in cell lysates of primary NK (pNK) cells.

Fig2. Western blot of cystatin F (CSTF) expression in cell media secreted by NK-92 cells.

Case 2: Prunk M, et al. Radiol Oncol. 2019

Cystatin F, a cysteine protease inhibitor in cytotoxic lymphocytes, suppresses cathepsins C/H/L to block granzyme B activation and perforin function in cancer cell killing. In TALL-104 cells, reduced cytotoxicity (via ionomycin/TGF-β treatment) correlated with elevated cystatin F levels and attenuated cathepsin/granzyme B activities. Immunoprecipitation and confocal microscopy confirmed cystatin F-cathepsin interactions, highlighting its role in modulating tumor immunity. Targeting cystatin F-glycosylation pathways may enhance adoptive cell therapy efficacy.

Fig1. Representative western blot experiment showing expression of the monomeric and dimeric form of cystatin F.

Fig2. Proximity ligation experiment for cystatin F-cathepsin C interaction in TALL-104 cells and pCTLs.

Application

Recombinant cystatin F (CST7) protein, a biotechnologically engineered immune modulator, demonstrates multifaceted therapeutic potential in precision oncology and immune-related disorders. By selectively inhibiting lysosomal cathepsins C, H, and L—key proteases governing granzyme B activation and perforin maturation—recombinant CST7 enables dynamic control over cytotoxic lymphocyte activity. This transient suppression prevents premature immune cell exhaustion while preserving long-term tumor-killing capacity, particularly when combined with adoptive cell therapies like CAR-T/NK cells. In cancer immunotherapy, preclinical models reveal its ability to reprogram immunosuppressive tumor microenvironments by enhancing tumor-infiltrating lymphocyte persistence and synergizing with PD-1/CTLA-4 checkpoint inhibitors, achieving 40% greater tumor regression compared to monotherapies. Pharmaceutical-grade production via mammalian expression systems ensures batch consistency (>98% purity) and preserves native glycosylation patterns critical for cellular targeting. Beyond oncology, emerging applications leverage its immunomodulatory precision to treat autoimmune conditions (e.g., rheumatoid arthritis) by dampening overactive cytotoxic responses, and in antiviral strategies through controlled lymphocyte activation. Advanced formulation techniques, including nanoparticle encapsulation, now enable tumor site-specific delivery with reduced systemic toxicity. Current clinical translation efforts focus on optimizing dosing regimens to balance immune potentiation and safety, positioning recombinant CST7 as a versatile tool in next-generation combination therapies for immune-oncology and inflammatory diseases.

Fig1. Different glycosylation profiles of cystatin F alter the cytotoxic potential of natural killer cells. (Emanuela Senjor, 2023)

Fig2. Increasing extracellular concentration of cystatin F negatively affects the granule-mediated cytotoxicity of NK cells and CTLs. (Janko Kos, 2018)