Anti-Mouse CD105 (Endoglin) [Clone MJ7/18] – Purified in vivo PLATINUM^TM Functional Grade

Clone MJ7/18 is a rat monoclonal antibody that specifically recognizes mouse CD105 (Endoglin), a marker predominantly expressed on vascular endothelial cells. In vivo applications of clone MJ7/18 in mice most commonly include:

• Tumor targeting and anti-angiogenic therapy: MJ7/18 has been used in vivo as a targeting agent for CD105-positive endothelial cells in tumor models, often conjugated as an immunotoxin, to selectively ablate tumor vasculature and inhibit tumor growth.
• Imaging: Radiolabeled MJ7/18 antibodies are applied for imaging tumor angiogenesis and monitoring CD105 expression in vivo using modalities such as SPECT or PET.
• Functional blocking and mechanistic research: MJ7/18 is used in vivo to block CD105 function, helping to elucidate its role in cardiovascular development, endothelial cell biology, and tumor angiogenesis.

Additional relevant applications include:

• In vivo antibody administration: The antibody is commercially available in low-endotoxin, functional grade preparations specifically for in vivo experiments, supporting its application in both mechanistic and therapeutic mouse studies.
• Immunohistochemistry and tissue staining of vascular endothelium: MJ7/18 is routinely used to label CD105-positive cells in mouse tissue sections to study endothelial distribution and changes under physiological and pathological conditions.
• Flow cytometric analysis of endothelial cells in blood or tissue samples: MJ7/18 is utilized in vivo or ex vivo for characterizing populations of endothelial cells in mouse models of inflammation, tumor growth, or vascular development.

In summary, MJ7/18 is employed in live mice for anti-angiogenic experimental therapies, imaging of tumor vasculature, and as a functional tool in research on vascular biology, particularly processes involving endothelial cells and their role in disease progression.

The antibody MJ7/18 is a rat monoclonal used to detect mouse CD105 (Endoglin), commonly as an endothelial cell marker and in studies of angiogenesis. In the literature, MJ7/18 is frequently used together with a set of established antibodies and proteins, depending on the experimental goal and context:

• Isotype-matched control antibodies: These are almost always used alongside MJ7/18 to confirm specificity in imaging, flow cytometry, or histological studies.
• Other endothelial or vascular markers:
  • CD31 (PECAM-1): Commonly used to identify endothelial cells and distinguish them from other cell types.
  • VE-cadherin (CD144): Another key endothelial marker, often co-stained to confirm endothelial specificity.
  • VEGF or its receptors (e.g., VEGFR2): Frequently analyzed in angiogenesis studies to assess vascular proliferation and compare with CD105 expression.
• Markers of proliferation or vascular activation:
  • Ki-67: Used to identify proliferating cells, including proliferating endothelial cells in tumors (often in tandem with CD105 staining).
  • α-SMA (alpha-smooth muscle actin): Used to identify pericytes or smooth muscle cells in angiogenesis studies, often in comparison to CD105-stained endothelium.
• Other species or clone anti-CD105 antibodies: For cross-validation (e.g., human-reactive or different clones in non-murine models) such as TRC105 or MAEND3.
• Control proteins/antigens:
  • Avidin/biotin systems: MJ7/18 is often biotinylated for conjugation, and avidin is used in microbubble or imaging platforms.
  • Radiolabeled variants: ^111In or ^125I-labeled MJ7/18 is used for in vivo imaging and compared with radiolabeled isotype controls.

These combinations are dictated by experimental context: for example, in flow cytometry, MJ7/18 is sometimes used with CD31 and viability dyes; in immunohistochemistry, with proliferation or pericyte markers; in imaging, with labeled or blocked controls.

Other studies may use antibodies for TGF-β receptor components or integrins when exploring pathways related to CD105/Endoglin function in vascular biology and angiogenesis.

In summary: Commonly paired antibodies/proteins with MJ7/18 include isotype controls, CD31, VE-cadherin, VEGF/VEGFR2, Ki-67, α-SMA, other anti-CD105 clones, avidin/biotin, and radiolabeled proteins, reflecting its central role as a vascular marker in angiogenesis and tumor biology research.

Key Scientific Findings from Clone MJ7/18 Citations

MJ7/18 is a well-characterized rat monoclonal antibody targeting CD105 (Endoglin) in mouse models. Its use in the scientific literature has helped elucidate both the biology of endothelial cells and the utility of MJ7/18 for cell isolation and characterization.

Biological Insights and Applications

• Endothelial Cell Marker: MJ7/18 is a pan-endothelial antibody used extensively for the isolation and identification of murine endothelial cells. It is recognized for its specificity and is commonly employed in applications such as flow cytometry, immunofluorescence, immunohistochemistry, immunoprecipitation, and Western blotting.
• Target Specificity and Epitope: The antibody is derived from inflamed mouse skin and recognizes the extracellular domain of the CD105/Endoglin protein, which is a major glycoprotein of vascular endothelium. CD105 exists as a 90 kDa glycoprotein that forms a disulfide-linked homodimer and is crucial for cell adhesion and embryonic angiogenesis.
• Minimal Off-Target Binding: MJ7/18 exhibits extremely weak (minimal) reactivity with early hematopoietic cells, underscoring its specificity for endothelial cells.
• Utility in Tumor Biology: Radiolabeled MJ7/18 (e.g., 111In-MJ7/18) has been shown to have intense activity at the tumor periphery—regions with high vascular density—suggesting its utility in mapping tumor-associated angiogenesis and potentially for imaging or targeting tumor vasculature.
• Molecular Weight Observations: The apparent molecular weight of CD105 detected by MJ7/18 varies depending on reduction state: ~180 kDa (non-reduced) and ~90 kDa (reduced), which can be useful for Western blot assays.

Technical and Methodological Findings

• Robust Performance Across Assays: MJ7/18 has been validated for multiple techniques, including FACS, IHC (frozen sections), immunoprecipitation, and Western blot, primarily in mouse systems. It is recommended for flow cytometric analysis at ≤0.5 µg per test, with titration suggested for optimal results.
• Storage and Stability: For long-term preservation, the antibody should be aliquoted and stored at -20°C or below, avoiding repeated freeze-thaw cycles.
• Available Conjugates: MJ7/18 is available in various conjugated forms (e.g., APC, PacBlue), facilitating multiplex and high-sensitivity flow cytometry experiments.

Summary Table: Key Features of MJ7/18

Conclusion

MJ7/18 is a highly specific and widely cited antibody for the study of mouse endothelial biology, particularly in the context of angiogenesis and vascular development. Its minimal cross-reactivity, robust performance across multiple assays, and availability in various conjugated forms make it a valuable tool in vascular biology research. Additionally, its use in imaging tumor vasculature highlights its potential translational applications.

Dosing regimens for clone MJ7/18 (anti-mouse CD105 antibody) vary significantly depending on the application, experimental goal, and mouse model. There is limited information in the search results regarding standardized in vivo dosing, but the available data suggest the following patterns:

• Immunohistochemistry (IHC), Immunofluorescence (IF), Immunocytochemistry (ICC):

  • Recommended concentration is 2–5 μg/ml for tissue sections or cell preparations.
  • One protocol applied 10 μg/ml overnight at 4°C for tissue sections.

• Flow Cytometry:

  • Used at amounts ≤0.5 μg (“per test” basis, typically for staining 10^6 cells).

• In Vivo Imaging and Biodistribution:

  • For radiolabeled antibody studies (e.g., ^111In-MJ7/18), the antibody is injected intravenously (i.v.), but specific microgram or mg/kg dosing per mouse is not always indicated in search summaries.
  • These studies emphasize accumulation and clearance in specific mouse models (often tumor-bearing), but details on non-labeled dosing regimens are not provided.

• Isotype and Applications:

  • Most applications involve mouse models and utilize the antibody in rat IgG2a format.

Dosing Comparison Across Mouse Models

Additional Notes

• Unlike antibodies such as anti-PD-1 or anti-CD3, standardized in vivo dosing regimens for MJ7/18 are not established in the literature or manufacturer protocols identified in the search results. Other antibodies frequently used in mouse models (e.g., anti-PD-1, anti-CD3) often use 100–500 μg per mouse per dose, typically given intraperitoneally at 2–4 day intervals, but there is no evidence these protocols apply directly to MJ7/18.
• MJ7/18 is primarily documented as an endothelial marker for experimental techniques rather than as an in vivo therapeutic or depleting agent.

In summary, clone MJ7/18 is predominantly used for ex vivo staining of mouse tissues and cells at concentrations between 2–10 μg/ml depending on the method, with no standardized dosing regimen established for in vivo functional studies across mouse models in the current literature. For any advanced or novel in vivo use, dose-finding and pilot studies are recommended.