CLDN18 Protein: Target Overview, Research Applications, and Selection Guide

15 products

Claudin 18 (CLDN18) is a member of the claudin family of tight junction proteins, which are essential components of epithelial barrier structures. CLDN18 exists in two main isoforms, CLDN18.1 and CLDN18.2, generated through alternative splicing. Among these, CLDN18.2 has emerged as a clinically relevant tumor-associated antigen, particularly in gastric and pancreatic cancers. Under normal physiological conditions, CLDN18.2 is largely confined to gastric mucosa and is buried within tight junctions, limiting antibody accessibility. However, in malignant transformation, tight junction disruption exposes CLDN18.2 on the cell surface, making it an attractive and highly specific therapeutic target.

CLDN18 Target Overview

CLDN18 is a four-pass transmembrane protein localized at tight junctions, functioning primarily in epithelial barrier maintenance. It plays roles in:

  • Regulation of paracellular permeability 
  • Maintenance of epithelial polarity 
  • Cell–cell adhesion 
  • Tumor-specific antigen exposure (CLDN18.2) 

A key feature of CLDN18.2 is its tumor-restricted accessibility, which distinguishes it from many broadly expressed membrane targets. While not a signaling receptor or enzyme, CLDN18.2 serves as a structural and targeting antigen, enabling selective antibody-based therapies.

CLDN18 Target Information

Target Name: CLDN18
Synonyms: Claudin-18; Claudin-18.2
UniProt ID: P56856
Target Class: Tight junction protein; transmembrane protein; tumor-associated antigen

CLDN18 Mechanism of Action

CLDN18.2 becomes exposed on tumor cells due to tight junction disruption and can be specifically targeted by therapeutic antibodies. Antibody binding activates immune effector mechanisms such as ADCC and CDC, leading to tumor cell lysis.

Key Research Applications of CLDN18 Protein

CLDN18 is primarily used in oncology and antibody development workflows, especially for CLDN18.2-targeted therapies.

1. Tumor Target Validation

  • Expression profiling in gastric and pancreatic cancers 
  • Surface exposure analysis in tumor vs normal tissue 
  • Biomarker validation for patient stratification 

2. Antibody Discovery and Engineering

  • Screening of anti-CLDN18.2 antibodies 
  • Epitope mapping and affinity optimization 
  • Fc engineering for enhanced effector function 

3. Immunotherapy Studies

  • ADCC and CDC functional assays 
  • Effector cell recruitment and activation studies 
  • Combination therapy evaluation 

4. Cell-Based Functional Assays

  • Membrane localization validation 
  • Internalization and antibody binding assays 
  • Flow cytometry and imaging-based assays

CLDN18 Experimental Workflows and Use Cases

  • Flow cytometry – surface expression detection 
  • Cell-based binding assays – antibody interaction 
  • Cytotoxicity assays – ADCC/CDC evaluation 
  • Immunohistochemistry – tissue distribution 
  • Co-culture assays – immune cell engagement 

As a membrane structural protein, CLDN18 is best suited for cell-based and antibody-mediated assays, rather than biochemical enzyme workflows.

Browse Our CLDN18 Products

Submit an inquiry or email inquiry@betalifesci.com for a customization request or bulk order quote.

Fast turnaround production is available at a affordable price point if none of our catalog products fits your desire specifications.

Filters

    15 products
    The purity of Biotinylated Human Claudin 18.2 VLP is greater than 95% as determined by SEC-HPLC.
    Biotinylated Full length Human Claudin 18.2 VLP, Active
    • Molecule: Claudin 18.2;
    • Species: Human;
    • Expression system: Mammalian Cell;
    • Sequence: Met1-Val261;
    CAT#: BLK-03253P

    Online Inquiry
    The purity of Human Claudin 18.2 VLP is greater than 95% as determined by SEC-HPLC.
    Recombinant Human Claudin 18.2 VLP, Active
    • Molecule: Claudin 18.2;
    • Species: Human;
    • Expression system: Mammalian Cell;
    • Sequence: Met1-Val261;
    CAT#: BLK-03250P

    Online Inquiry
    Immobilized Biotinylated Human Claudin 18.2 Nanodisc, His Tag at 1ug/ml (100ul/well) on the streptavidin precoated plate (5ug/ml). Dose response curve for Anti-Claudin18.2 Antibody, hFc Tag with the EC50 of 52.2ng/ml determined by ELISA.
    Biotinylated Human Claudin 18.2 Nanodisc, Active
    • Molecule: Claudin 18.2;
    • Species: Human;
    • Expression system: Mammalian Cell;
    • Tag: C-His;
    • Sequence: Met1-Val261;
    CAT#: BLK-03186P

    Online Inquiry
    Sale
    SDS-PAGE analysis of Human CLDN18 (Claudin-18) - Recombinant Protein, CAT# BLT-08536P showing >90% purity under 15% SDS-PAGE (Reduced)
    Human CLDN18 (Claudin-18) - Recombinant Protein
    • Molecule: CLDN18;
    • Species: Human;
    • Expression system: E.coli;
    • Tag: N-6His+sumo;
    • Sequence: 28-80;
    CAT#: BLT-08536P

    Save $139
    Western BlotPositive WB detected in: KATO3-18.2 whole cell lysate, NIH3T3-18.1 whole cell lysateAll lanes: CLDN18 antibody at 1:500SecondaryGoat polyclonal to rabbit IgG at 1/50000 dilutionPredicted band size: 28 kDaObserved band size: 28 kDa
    IHC image of CLDN18 Antibody diluted at 1:50 and staining in paraffin-embedded human stomach tissue performed on a Leica BondTM system. After dewaxing and hydration, antigen retrieval was mediated by high pressure in a citrate buffer (pH 6.0). Section was blocked with 10% normal goat serum 30min at RT. Then primary antibody (1% BSA) was incubated at 4°C overnight. The primary is detected by a Goat anti-rabbit polymer IgG labeled by HRP and visualized using 0.05% DAB.
    Rabbit anti-Human CLDN18 Polyclonal Antibody
    CAT#: BLC-01879A
    The purity of Human Claudin 18.2 VLP is greater than 95% as determined by SEC-HPLC.
    Recombinant Human Claudin 18.2 Protein-VLP, Active
    • Molecule: CLDN18;
    • Species: Human;
    • Expression system: Mammalian Cell;
    CAT#: BLK-02368P-100UG

    Online Inquiry
    Greater than 85% as determined by SDS-PAGE.
    Recombinant Human Claudin-18 (CLDN18) Protein (GST)
    • Molecule: CLDN18;
    • Species: Human;
    • Expression system: E.coli;
    • Tag: GST;
    • Sequence: Protein Fragment;
    CAT#: BLC-07601P

    Online Inquiry
    Western Blot this product is detected by Mouse anti-6*His monoclonal antibody.The three bands respectively correspond to monomer, Homodimer, Homotrimer
    Activity Measured by its binding ability in a functional ELISA. Immobilized human CLDN18.2 ) at 5 μg/ml can bind anti-CLDN18.2 recombinant Monoclonal Antibody , the the EC 50 is 5.225-9.256 ng/ml. Biological Activity Assay
    Recombinant Human Claudin-18.2 (CLDN18.2) Protein (His), Active
    • Molecule: CLDN18.2;
    • Species: Human;
    • Expression system: Mammalian Cell;
    • Tag: His;
    • Sequence: Full Length Protein;
    CAT#: BLC-05807P

    Online Inquiry
    this product is detected by Mouse anti-6*His monoclonal antibody.
    Activity Measured by its binding ability in a functional ELISA. Immobilized Macaca fascicularis CLDN18 at 5 μg/ml can bind Anti-CLDN18.2 recombinant Antibody , the EC 50 is 2.806-3.641 ng/ml. Biological Activity Assay
    Recombinant Cynomolgus Monkey Claudin (CLDN18) Protein (His), Active
    • Molecule: CLDN18;
    • Species: Cynomolgus Monkey;
    • Expression system: Mammalian Cell;
    • Tag: His;
    • Sequence: Full Length Protein;
    CAT#: BLC-05749P

    Online Inquiry
    this product is detected by Mouse anti-6*His monoclonal antibody.
    Activity Measured by its binding ability in a functional ELISA. Immobilized Mouse Cldn18 at 5 μg/ml can bind Anti-CLDN18.2 recombinant antibody , the EC 50 is 6.115-11.01 ng/mL. Biological Activity Assay
    Recombinant Mouse Claudin-18 (CLDN18) Protein (His), Active
    • Molecule: Cldn18;
    • Species: Mouse;
    • Expression system: Mammalian Cell;
    • Tag: His;
    • Sequence: Full Length Protein;
    CAT#: BLC-05746P

    Online Inquiry
    Greater than 90% as determined by SDS-PAGE.
    Recombinant Human Claudin-18 (CLDN18) Protein (His)
    • Molecule: CLDN18;
    • Species: Human;
    • Expression system: E.coli;
    • Tag: His;
    • Sequence: Protein Fragment;
    CAT#: BLC-00354P

    Online Inquiry
    Biotinylated Human CLDN18.2 Protein (N-6His, C-Avi)V2
    • Molecule: CLDN18.2;
    • Species: Human;
    • Expression system: E.coli;
    • Tag: His&Avi;
    • Sequence: extracellular;
    CAT#: BL-2572NP

    Online Inquiry
    BL-2529NP: Greater than 70% as determined by reducing SDS-PAGE. (QC verified)
    Recombinant Human CLDN18.2 Protein (N-Twin strep-Flag)
    • Molecule: CLDN18.2;
    • Species: Human;
    • Expression system: Mammalian Cell;
    • Tag: Twin-strep&Flag;
    • Sequence: Met1-Ala200;
    CAT#: BL-2529NP

    Online Inquiry
    BL-2260NP: Greater than 95% as determined by reducing SDS-PAGE. (QC verified)
    Recombinant Human CLDN18.1 Protein (N-8His)
    • Molecule: CLDN18.1;
    • Species: Human;
    • Expression system: E.coli;
    • Tag: His;
    • Sequence: Asp28-Leu76;
    CAT#: BL-2260NP

    Online Inquiry
    BL-2259NP: Greater than 95% as determined by reducing SDS-PAGE. (QC verified)
    Recombinant Human Claudin-18.2 Protein (N-8His)
    • Molecule: Claudin-18.2;
    • Species: Human;
    • Expression system: E.coli;
    • Tag: His;
    • Sequence: Asp28-Leu76;
    CAT#: BL-2259NP

    Online Inquiry