Anti-Mouse EpCAM (CD326) [Clone G8.8] — Purified in vivo GOLD^TM Functional Grade

Common in Vivo Applications of Clone G8.8 in Mice

Clone G8.8 is a rat monoclonal antibody with high specificity for mouse EpCAM (CD326), a cell-surface glycoprotein prominently expressed in epithelial and thymic epithelial cells. Its in vivo applications are primarily focused on cell identification, isolation, and functional manipulation.

Cell Population Identification and Isolation

• Isolation and Purification: G8.8 is widely used to isolate and purify mouse thymic epithelial cells and other EpCAM-expressing (EpCAM+) cell populations in vivo, leveraging techniques such as flow cytometry and magnetic bead-based cell sorting. This enables researchers to selectively enrich epithelial cell subsets from complex tissues for downstream analysis.
• Marker Studies: The antibody is employed to identify and localize alveolar progenitor and stem cells in the mouse lung in vivo, mapping their activity and distribution during development and regeneration.

Functional Manipulation and Therapy

• CAR-T Cell Engineering: The single-chain variable fragment (scFv) from G8.8 is used to construct mouse EpCAM-specific chimeric antigen receptor (CAR) T cells. These CAR-T cells are then adoptively transferred into mice to study in vivo targeting and anti-tumor efficacy against EpCAM-expressing malignancies.
• Exclusion of Human and Rat EpCAM: G8.8 specifically recognizes mouse EpCAM and does not cross-react with human or rat homologs, making it ideal for murine-specific in vivo studies.

Key Experimental Techniques

• Flow Cytometry and Cell Sorting: G8.8 is routinely used for in vivo and ex vivo flow cytometric analysis and cell sorting to identify, quantify, and isolate EpCAM+ cells from mouse tissues.
• Immunohistochemistry (IHC) and Immunofluorescence (IF): The antibody is also employed for in situ visualization of EpCAM expression in tissue sections, providing spatial information about epithelial cell distribution.
• In Vivo Depletion and Functional Studies: Some protocols may use G8.8 for in vivo antibody-mediated depletion of EpCAM+ cells to study their functional roles in organogenesis, tissue homeostasis, and disease models, although the referenced materials primarily emphasize isolation and engineering applications.

Summary Table

Conclusion

Clone G8.8 is a versatile reagent central to the study of murine epithelial biology in vivo, with main uses in cell isolation, phenotyping, functional manipulation (e.g., CAR-T therapy), and spatial mapping of epithelial cell populations. Its strict specificity for mouse EpCAM ensures reliable results in murine models without cross-reactivity with human or rat tissues.

Commonly used antibodies or proteins with G8.8 (anti-mouse EpCAM/CD326) in the literature include markers for immune and epithelial cell identification, particularly in immunophenotyping, tissue characterization, and cell isolation experiments.

Commonly co-used antibodies:

• CD3: T cell marker
• CD45: pan-leukocyte marker
• CD4: helper T cell marker
• CD8: cytotoxic T cell marker
• CD19: B cell marker

These antibodies are frequently used alongside G8.8 in studies involving lymphocyte subset identification and characterization, especially in mucosal immunology and cancer research. In such studies, G8.8 is used to label epithelial cells, while the additional markers help classify and quantify various leukocyte populations in the same sample.

Other proteins and reagents:

• E-cadherin and other epithelial cell markers are often employed in conjunction with EpCAM staining to further delineate epithelial cell subtypes, though EpCAM (G8.8) is typically the primary epithelial marker in mouse tissues.
• Viability dyes are also commonly used for accurate cell counting and exclusion of dead cells during flow cytometry and cell sorting.

Sample usage contexts:

• Flow cytometry and immunohistochemistry studies, where immune cell infiltrates within epithelial tissues are identified using panels containing G8.8 together with the above immune cell markers.
• Cell isolation from tissues, where epithelial cells (EpCAM+) are separated from leukocytes (CD45+, CD3+, etc.) using combinations of these antibodies.

In summary, G8.8 is most often paired with antibodies against CD3, CD45, CD4, CD8, and CD19 in studies focused on mouse epithelial and immune cell interactions or tissue profiling.

Clone G8.8 is a well-established rat monoclonal antibody against mouse EpCAM (CD326), widely cited in scientific literature for its specificity and utility in immunological and epithelial cell research.

Key findings and uses from the literature:

• Specificity: G8.8 specifically recognizes murine (mouse) EpCAM (CD326) and does not cross-react with human or rat EpCAM.
• Applications: The antibody has been routinely used for:
  • Flow cytometry (FACS) to identify and sort epithelial and thymic epithelial cells.
  • Immunohistochemistry (IHC) and immunofluorescence (IF) for tissue staining, commonly of frozen sections.
  • Immunoprecipitation (IP) and Western blotting for protein studies and cell isolation.
• Biological insights enabled:
  • Cell sorting and purification: G8.8 has enabled highly specific purification of mouse epithelial and thymic epithelial cells for downstream applications.
  • Developmental biology: It has facilitated studies on thymic development and stem cell biology, with citations in stem cell research (e.g., Fischedick et al., Stem Cell Res. 2014).
  • Immunology: Frequently used for characterization of epithelial progenitors, and immune cell interactions in mouse models.
  • Tissue engineering/regeneration: G8.8 is referenced in research on tissue engineering and epithelial cell regeneration (e.g., Walmsley et al., Tissue Eng Part C Methods. 2015).
• Technical details:
  • Isotype: Rat IgG2a.
  • Epitope: Targets a conformational epitope on the extracellular domain of murine EpCAM.
  • Performance: Not recommended for detection of human or rat EpCAM as no cross-reactivity has been observed.
  • Hybridoma availability: The G8.8 hybridoma is widely available through repositories such as the Developmental Studies Hybridoma Bank (DSHB).
• Citations: Key publications that define and repeatedly utilize clone G8.8 include:
  • PMID:8617310 (defining citation)
  • PMID:16177073
  • PMID:8566052
  • PMID:2016514
  • Numerous more recent citations across developmental, immunological, and regenerative biology journals.

Summary of impact:
G8.8 is a foundational tool in mouse epithelial cell biology, facilitating a wide range of applications from cell sorting to immunophenotyping, and is referenced extensively for murine-specific studies of EpCAM function, development, and disease.

Dosing regimens of clone G8.8 (a rat monoclonal antibody to mouse EpCAM/CD326) are not standardized across mouse models; they are typically determined empirically and tailored to the experimental context. There is no widely published universal in vivo dosing protocol for clone G8.8, and dose, route, and frequency can differ based on the intended application (e.g., flow cytometry vs. functional in vivo studies) and mouse strain.

Key context and supporting details:

• Empirical Optimization: Dosing is often optimized based on experimental requirements, with each lab or study potentially using different concentrations, injection schedules, and routes depending on the goal (e.g., cell depletion, blocking, or detection).
• Typical Laboratory Usage: For flow cytometry and ex vivo applications, recommendations are around ≤0.06–0.25 µg per million cells in 100 µl, with titration suggested for best performance. These recommendations do not translate directly to in vivo systemic dosing.
• Dosing in Mouse Models: No published source provides a standard in vivo dose for clone G8.8 comparable to common depleting antibodies (like anti-CD4 or anti-CD8), which are often used at 100–300 µg/mouse via intraperitoneal injection. For G8.8, in vivo dosing is usually determined based on factors such as:
  • Mouse strain and immunological status (e.g., wild-type vs. immunodeficient)
  • Application (cell tracking, targeting, or depletion)
  • Experimental endpoints (e.g., duration of effect, need for repeated administration).
• Supplier Recommendations: Manufacturers and suppliers also refrain from specifying in vivo dosing, instead advising that end-users titrate for optimal effect in their model.

In summary, dosing regimens for clone G8.8 vary and should be empirically optimized for each mouse model and research application. There is no evidence of a universal or commonly accepted protocol in the literature or major supplier documentation. If using clone G8.8 in vivo, pilot titration to assess efficacy and toxicity in the specific experimental and mouse context is strongly recommended.