CLDN3 antibodies are immunoglobulins designed to bind Claudin-3, a four-transmembrane domain protein critical for tight junction formation in epithelial cells. CLDN3 is aberrantly expressed in cancers such as ovarian, breast, pancreatic, and prostate malignancies, making it a therapeutic and diagnostic target . These antibodies recognize extracellular loops (ECL1 or ECL2) of CLDN3, enabling selective targeting of cancer cells .
Antigens: CLDN3-overexpressing CHO-K1 cells and CLDN3-embedded lipoparticles were used to generate the human IgG1 antibody h4G3 via scFv phage display .
Cross-Reactivity: h4G3 binds human and mouse CLDN3 without cross-reactivity to other claudins (e.g., CLDN4, CLDN6) .
Bispecific Antibodies: Recent advances include EpCAM×CLDN3 bispecific antibodies (BsAbs) created using Knob-into-hole and CrossMab technologies, enhancing tumor specificity .
h4G3 exhibits sub-nanomolar affinity (KD ≈ 0.7 nM) for cell-surface CLDN3, validated by surface plasmon resonance .
KM3907, another monoclonal antibody, targets ECL1 of CLDN3/4 and shows CDC (complement-dependent cytotoxicity) activity .
h4G3 activates FcγRIIIa (CD16a) on natural killer cells, inducing ADCC in CLDN3-positive cancers (e.g., ovarian OVCAR-3, breast MCF-7) .
Dose-dependent cytotoxicity correlates with CLDN3 expression levels .
Fluorescent/Radioisotope Conjugates: CLDN3 antibodies labeled with ¹¹¹In or FNR648 showed tumor-specific uptake in xenograft models (20.4% ID/g in OVCAR-3 tumors) .
Immunohistochemistry (IHC): Validated in renal, gallbladder, and ovarian carcinomas (Fig. 2–9, ).
Bispecific ADCs (BsADCs) targeting CLDN3 and EpCAM demonstrated enhanced cytotoxicity in dual-antigen-expressing tumors (IC₅₀ = 0.72 μg/mL in OVCAR-3) .
h4G3: Potential for CAR-T cell therapy due to tumor-localizing properties in xenograft models .
| Antibody | Target Region | Cross-Reactivity | Activity |
|---|---|---|---|
| h4G3 | ECL2 | None | ADCC |
| KM3907 | ECL1 | CLDN4 | ADCC/CDC |
| IgGH6 | ECL2 | None | Internalization |
Fluorescence-conjugated h4G3 localized preferentially to CLDN3-positive tumors in mice, with minimal off-target accumulation .
BsADC 3: Reduced tumor growth in HCT116 (colon cancer) and SNU-5 (gastric cancer) models .
No significant toxicity reported in murine models, attributed to CLDN3’s restricted expression in normal tissues .
Given the context of "CLE3 Antibody" and the need for FAQs that reflect scientific depth, I will create a collection of questions and answers relevant to academic research scenarios. Since specific information on "CLE3 Antibody" is not directly available in the search results, I will focus on general principles related to antibody research, particularly emphasizing experimental design, data analysis, and methodological considerations.
When designing experiments to evaluate antibody specificity and efficacy, researchers typically follow these steps:
Antigen Selection: Choose specific antigens or proteins that the antibody targets.
Cell Culture: Use cell lines expressing the target antigen for in vitro studies.
Western Blot and ELISA: Perform Western blotting and ELISA to assess antibody binding specificity and affinity.
Immunofluorescence: Conduct immunofluorescence microscopy to visualize antibody-antigen interactions in cells.
In Vivo Models: Use animal models to study antibody efficacy and safety in vivo.
To resolve data contradictions:
Re-evaluate Experimental Conditions: Check for differences in experimental conditions, such as antibody concentrations or incubation times.
Validate Antibody Specificity: Use multiple methods (e.g., Western blot, ELISA, and immunofluorescence) to confirm antibody specificity.
Consider Sample Variability: Account for biological variability in samples, especially in cell culture or animal studies.
Statistical Analysis: Apply appropriate statistical tests to determine if observed differences are significant.
To engineer antibodies for improved specificity and affinity:
Mutagenesis: Use site-directed mutagenesis to modify key residues in the antibody's variable regions.
Phage Display: Employ phage display libraries to screen for high-affinity variants.
Computational Modeling: Utilize computational tools to predict and design optimal antibody structures.
Chimeric and Humanized Antibodies: Develop chimeric or humanized antibodies to reduce immunogenicity in therapeutic applications.
To validate antibody specificity and performance:
Western Blot and ELISA: Use these techniques to assess antibody binding to specific antigens.
Immunofluorescence and Immunohistochemistry: Validate antibody staining patterns in cells and tissues.
Blocking Peptide Controls: Use blocking peptides to confirm specificity by competing with the antibody for antigen binding.
Cross-reactivity Tests: Test for cross-reactivity with other proteins to ensure specificity.
To study ADCP:
In Vitro Assays: Use cell culture models to assess the ability of antibodies to induce phagocytosis by immune cells.
Flow Cytometry: Measure the engulfment of antibody-coated targets by phagocytic cells.
In Vivo Models: Evaluate ADCP in animal models to assess therapeutic efficacy and safety.
Implications: ADCP is crucial for therapeutic antibodies targeting cancer cells, enhancing their clearance by the immune system.
To predict antibody structures:
Deep Learning Models: Utilize tools like ABodyBuilder2 to predict antibody structures based on sequence data.
Molecular Dynamics Simulations: Perform simulations to refine predicted structures and assess stability.
Implications: Predicted structures can guide antibody engineering efforts by identifying regions for mutagenesis to improve affinity or specificity.
To optimize antibody storage:
Temperature Control: Store antibodies at appropriate temperatures (e.g., -20°C for long-term storage).
Buffer Composition: Use buffers that maintain antibody stability, such as those with stabilizing agents like trehalose.
Avoid Freeze-Thaw Cycles: Minimize freeze-thaw cycles to prevent degradation.
Aliquoting: Aliquot antibodies to reduce exposure to temperature fluctuations during handling.
To design bispecific antibodies:
Antigen Selection: Choose two antigens that are relevant for therapeutic targeting.
Engineering Strategies: Use formats like IgG-like molecules or single-chain variable fragments (scFv) to create bispecific antibodies.
In Vitro and In Vivo Testing: Evaluate bispecific antibodies in cell culture and animal models to assess efficacy and safety.
Implications: Bispecific antibodies can enhance therapeutic outcomes by targeting multiple pathways simultaneously.
To assess and mitigate cross-reactivity:
Western Blot and ELISA: Use these methods to screen for binding to non-target proteins.
Blocking Peptide Controls: Employ blocking peptides to confirm specificity.
Optimize Antibody Concentrations: Adjust antibody concentrations to minimize non-specific binding.
Use Specificity-Enhancing Techniques: Apply techniques like affinity purification to enhance antibody specificity.
Advantages of NADAs include:
Improved Reproducibility: NADAs can offer more consistent performance across batches.
Ethical Considerations: Reduced reliance on animal sources.
Challenges: Higher production costs and potential limitations in diversity compared to traditional antibodies.
Implications: NADAs are promising alternatives for research applications requiring high reproducibility and ethical considerations.