Recombinant Human EBAG9 protein(Arg28-Ser213), His-tagged

• Cat.No.: EBAG9-457H
• Product Overview: Recombinant Human EBAG9 (O00559) (Arg28-Ser213) was expressed in E. coli with a polyhistidine tag at the N-terminus.

Specification

• Species: Human
• Source: E.coli
• Tag: His
• Protein Length: 28-213 a.a.
• Form: Lyophilized from sterile PBS, pH 7.4. Normally 5 % - 8 % trehalose, mannitol and 0.01% Tween80 are added as protectants before lyophilization.
• Molecular Mass: The recombinant human EBAG9 consists of 201 amino acids and predicts a molecular mass of 23 KDa. It migrates as an approximately 33 KDa band in SDS-PAGE under reducing conditions.
• Purity: > 90 % 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: EBAG9 estrogen receptor binding site associated, antigen, 9 [ Homo sapiens ]
• Official Symbol: EBAG9
• Synonyms: EBAG9; estrogen receptor binding site associated, antigen, 9; receptor-binding cancer antigen expressed on SiSo cells; EB9; RCAS1; cancer associated surface antigen; cancer-associated surface antigen RCAS1; estrogen receptor-binding fragment-associated gene 9 protein; PDAF
• Gene ID: 9166
• mRNA Refseq: NM_004215
• Protein Refseq: NP_004206
• MIM: 605772
• UniProt ID: O00559

Case Study

Case 1: Wirges A, et al. Mol Ther. 2022

EBAG9 silencing enhances CAR T-cell efficacy by counteracting its immune checkpoint role in cytolytic enzyme suppression. miRNA-driven EBAG9 knockdown boosts tumor eradication in xenotransplant models, requiring lower therapeutic doses without elevating cytokine release syndrome risks. Integrated retroviral CAR/TCR-EBAG9 silencing streamlines manufacturing, supporting safer, high-efficacy adoptive T-cell therapies.

Fig1. RNAi-mediated reduction of EBAG9 protein level.

Fig2. Western blot of EBAG9 protein expression in sorted CD8+ IgG+ cells.

Case 2: Tanaka H, et al. J Transl Med. 2014

RCAS1 promotes immune evasion in oral squamous cell carcinoma (OSCC) by inducing lymphocyte apoptosis via membrane-bound and soluble forms. Overexpressed in metastatic SQUU-B cells, RCAS1 enhances apoptosis in co-cultured K562 leukemia cells, while knockdown reduces this effect. Soluble RCAS1 retains pro-apoptotic activity, highlighting its role in tumor microenvironment immune suppression.

Fig1. RCAS1 protein was diffusely expressed in both cytoplasm and on membranes in all OSCC cell lines and SiSo, and was especially strong in SQUU-B cells.

Fig2. Mean fluorescence intensity (MFI) of membranous RCAS1 was significantly higher in SQUU-B than in the other 3 OSCC cell lines.

Application

1. Applications of Recombinant EBAG9 Protein in Cancer Immunology Recombinant EBAG9 protein is a pivotal tool for studying immune evasion mechanisms in cancer. As an immune checkpoint regulator, EBAG9 suppresses cytotoxic T lymphocyte (CTL) function by inhibiting granzyme release, enabling tumors to bypass immune surveillance. Researchers leverage recombinant EBAG9 to model tumor microenvironments, screen for inhibitors targeting its immunosuppressive activity, and engineer adoptive T-cell therapies. Preclinical studies demonstrate that neutralizing EBAG9 enhances CAR T-cell efficacy, reducing therapeutic doses while maintaining safety profiles. 2. Therapeutic Potential and Biomarker Development In cancer immunotherapy, recombinant EBAG9 aids in identifying biomarkers linked to T-cell exhaustion and therapy resistance. Its role in suppressing CTL activity correlates with poor prognosis in hormone-driven cancers (e.g., breast, ovarian), making it a candidate for combination therapies with PD-1/CTLA-4 inhibitors. By mimicking EBAG9’s immunosuppressive effects in vitro, scientists optimize strategies to disrupt its interaction with cytoskeletal proteins, thereby restoring T-cell cytotoxicity. 3. Challenges and Future Directions Despite its promise, challenges include optimizing recombinant EBAG9’s stability for in vivo use and minimizing off-target effects in gene-edited therapies. Advances in CRISPR screening and nanoparticle delivery systems may refine its application. Future research should focus on clinical validation, particularly in EBAG9-overexpressing tumors, to advance personalized immunotherapies and improve patient outcomes.

Fig1. EBAG9 plays a physiological role in bone maintenance by promoting autophagy together with its interactor TM9SF1. (Kotaro Azuma, 2024)