CLDN18 Research Reagents

Claudin-18, also known as CLDN18, belongs the Claudin (CLDN) protein family discovered by ShoichiroTsukita and colleagues in 1998. Claudins are crucial components of tight junctions which are specialized membrane domains at the most apical region of polarized epithelial and endothelial cells. Claudins are found in almost all vertebrates. For most species there are only a few Claudins, but humans have 26 Claudins except for the CLDN-13 gene.

CLDN18 is a major constituent of tight junctions in lung and stomach epithelia and has two isoformes, CLDN18.1 and Claudin 18.2. CLDN18.1 is mainly expressed in the lung, CLDN18.2 is mainly expressed in gastric epithelial cells, and CLDN18.2 is only expressed in differentiated epithelial cells on the gastric mucosa, and is not expressed in any other healthy tissue normal physiological conditions. However, it is highly expressed in primary malignant tumors such as gastric, breast, colon and liver cancers. Both CLDN18.1 and CLDN18.2 consist of 261 amino acids, have four transmembrane domains and two extracellular loops (extracellular loops: ECL1, ECL2), and their NH2 and COOH ends are both intracellular . CLDN18.1 and CLDN18.2 differ by only 7 amino acid residues in the approximately 50 amino acid sequence of ECL1.

Currently, CLDN18.2 is the most well-studied Claudin family protein. In normal tissues, the expression of Claudin is highly tissue-specific, expressed only in differentiated epithelial cells buried in the gastric mucosa, and the monoclonal antibody in normal tissues is basically undetectable. However, the occurrence of malignant tumors can lead to the destruction of tight junctions, exposing the CLDN18.2 epitope on the surface of tumor cells as a specific target.

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Popular Product

● Recombinant Human Claudin-18.2(CLDN18.2)-VLPs (Active) (CSB-MP005498HU(A5))

Validated Data

The binding activity of antigen-antibody validated by functional ELISA

Immobilized human CLDN18.2 at 5 μg/ml can bind anti-CLDN18.2 recombinant Monoclonal Antibody (CSB-RA005498A1HU), the the EC₅₀ is 5.225-9.256 ng/ml.

The accuracy of structure determined
by TEM

The presence of VLP-like structures was confirmed by TEM

● Claudin-18.2 Monoclonal Antibody (ELISA, FC) (CSB-RA005498A1HU)

Validated Data

The binding activity of antigen-antibody validated by functional ELISA

Immobilized Human CLDN18.2 (CSB-MP005498HU(A5)) at 5 μg/mL can bind Anti-CLDN18.2 recombinant antibody, the EC₅₀ is 6.554-27.87 ng/mL.

The binding activity of antibody-over-expressing cells validated by FC

Untransfected KATO3 cells (green line), transfected Human CLDN18.2 KATO3 stable cells (red line) and transfected Human CLDN18.1 NIH-3T3 stable cells (blue line) were stained with anti-CLDN18.2 antibody (2µg/1*10⁶ cells), washed and then followed by FITC-conjugated anti-Human IgG Fc antibody and analyzed with FC.