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

Clone MJ7/18, a rat anti-mouse CD105 (endoglin) monoclonal antibody, has been utilized in several in vivo applications in mice, primarily targeting endothelial cells and tumor vasculature.

Tumor Imaging and Therapy

The most prominent in vivo application involves tumor-targeted imaging and therapy. When labeled with radioactive isotopes such as indium-111 (¹¹¹In), the MJ7/18 antibody can be used for molecular imaging of tumors. The antibody demonstrates intense activity in the peripheral regions of tumors where the highest concentration of blood vessels is found. This distribution pattern makes it particularly useful for visualizing tumor vasculature.

Immunotoxin-Based Cancer Treatment

MJ7/18 has been developed as an immunotoxin conjugate for cancer therapy in mouse models. When conjugated to the toxin Ngb (forming MJ7-Ngb), the antibody was tested in C57BL/6J mice bearing B16MEL4A5 melanoma tumors. The treatment protocol involved administering the immunotoxin at 12-hour intervals after tumors became palpable, typically 1-2 weeks post-cell injection. This approach exerted significant inhibitory effects on tumor growth compared to controls, with some animals showing complete or partial tumor remission. Treated animals exhibited fibrous material at former tumor sites with minimal proliferating cells, indicating successful tumor destruction.

Endothelial Cell Targeting

As a pan-endothelial marker, MJ7/18 targets vascular endothelial cells throughout the body, though it shows minimal reactivity with early hematopoietic cells. This specificity makes it valuable for studying angiogenesis and vascular biology in living mice, particularly in contexts where endothelial cell proliferation is increased, such as in tumor vasculature.

Beyond MJ7/18, which targets murine CD105 (endoglin), commonly used antibodies or proteins in combination studies largely depend on the specific research context. However, several patterns emerge in the literature:

• Isotype-matched control antibodies: Studies frequently use isotype controls alongside MJ7/18 to confirm specificity and rule out nonspecific binding.
• Endothelial and vascular markers: Since MJ7/18 marks endothelial cells, other endothelial markers (e.g., anti-CD31/PECAM-1, anti-VEGFR2/Flk-1) are often co-used for comparative or multiplex immunostaining/isolation of endothelial subsets, although these specific antibodies are not explicitly named in the provided search results.
• Other CD105 antibodies: In comparative work, different anti-CD105 clones (e.g., MAEND3 in canine models, TRC105 in murine models) are used to validate cross-reactivity or comparative performance in imaging and functional studies.
• Biotinylated or conjugated analogs: MJ7/18 is often used in a labeled format (e.g., radiolabeled with ^111In or ^125I, or biotinylated for use with streptavidin-conjugates) to enable imaging or cell sorting.
• Microbubble-conjugated proteins: In molecular imaging studies, MJ7/18-biotin is attached to avidin-modified microbubbles for ultrasound- or fluorescence-based angiogenesis imaging in vivo, with parallel use of control mAbs for specificity validation.

These selections are determined by the need to:

• Validate specificity of MJ7/18
• Distinguish endothelial cell populations
• Enable imaging, isolation, or quantification of endothelial cells in various experimental contexts

Published literature routinely pairs MJ7/18 with:

• An isotype-matched IgG control
• Antibodies against alternative endothelial markers (CD31, VEGFR2, sometimes indirectly stated by context)
• Conjugates (fluorophores, enzymes, radionuclides, or microbubbles) for detection or imaging

If you are searching for the most common co-used reagents, start with controls and anti-CD31, and, if your application is imaging, consider labeled or conjugated versions for multiplexed protocols.

The key findings from clone MJ7/18 citations in scientific literature center on its role as a monoclonal antibody targeting CD105 (Endoglin), a major glycoprotein expressed on vascular endothelial cells, and its application for isolating and characterizing murine endothelial cells. MJ7/18 is widely cited for use in immunological assays where identification and study of endothelial cells are crucial, particularly in angiogenesis and cancer research.

Essential details and scientific context:

• Antigen Targeted: MJ7/18 specifically binds to the extracellular domain of CD105 (Endoglin), a disulfide-linked homodimer with a molecular weight ~90 kDa, highly expressed by vascular endothelial cells and involved in angiogenesis and cellular adhesion.
• Species Reactivity: It is primarily reactive with mouse CD105 protein, which makes it foundational in murine models of vascular biology and cancer.
• Immunogen: The antibody was raised using inflamed mouse skin, ensuring selectivity for endothelial markers.
• Recommended Applications: Frequently cited uses include:
  • Flow cytometry (FACS) for cell sorting and population characterization.
  • Immunofluorescence and immunohistochemistry for tissue-based localization studies.
  • Immunoprecipitation and Western blotting for biochemical analysis of CD105/Endoglin expression.
• Scientific Impact:
  • MJ7/18 is often used to isolate murine endothelial cells, serving as a "pan endothelial marker" with minimal reactivity to hematopoietic cells.
  • It enabled intense labeling in tumor vasculature, especially at the tumor periphery where vessel density is highest, making it a valuable tool in angiogenesis and cancer microenvironment studies.
  • Its use in studies of embryonic development and vascular biology is based on CD105’s role in angiogenesis.
• Storage and Handling: Scientific protocols emphasize short-term storage at 4°C and long-term storage at -20°C or -80°C to maintain antibody activity.
• Reproducibility and Standardization: Cited in numerous product sheets and protocols, MJ7/18 provides a standardized reagent for endothelial research, making comparative studies across labs and experiments feasible.

Representative findings:

• MJ7/18 was pivotal in demonstrating vessel distribution in tumor models, facilitating targeted imaging and intervention strategies focused on the angiogenic periphery.
• Protocols using MJ7/18 have established clear methods for mouse cell isolation and tissue staining, supporting reliable reproducibility in endothelial cell research.
• MJ7/18 has minimal cross-reactivity with early hematopoietic cells, reinforcing its specificity as an endothelial cell marker in mouse models.

Summary Table: Core characteristics of clone MJ7/18 citations

Alternative interpretations (e.g., MJ7/18 as a clone number in unrelated fields) are not supported by the citations currently indexed; all results refer to its use as an antibody in vascular and cell biology research.

Dosing regimens of clone MJ7/18 (anti-mouse CD105/Endoglin) for in vivo use in mouse models typically involve intraperitoneal (i.p.) injection at a dose of 100 μg per mouse every other day in tumor models. This regimen is documented in a preclinical hepatocellular carcinoma (HCC) model using BALB/c mice, where MJ7/18 was utilized for anti-angiogenic or tumor growth studies.

Essential context and supporting details:

• Dose and Frequency: The most clearly reported regimen is 100 μg/mouse i.p. every other day.
• Application: This dosing is specific to an anti-tumor setting, often combined with therapies such as sorafenib for potential additive or synergistic effects.
• Route of Administration: Intraperitoneal injection (i.p.) is standard for in vivo depleting or blocking studies.
• Duration: The duration of dosing is coordinated with tumor monitoring and experimental endpoints; for the cited regimen, dosing continued until study completion (tumor measurement every other day).

Variation Across Mouse Models:

• The search results provide limited evidence for major variation in dosing regimen by mouse model; the principal reported strategy is 100 μg every other day, regardless of specific tumor type or mouse strain in preclinical studies.
• Other antibody clones (e.g., anti-PD-1, anti-CD3) have widely diverse dosing regimens depending on their target, indication, and model, sometimes ranging from 5–500 μg/mouse and dosing intervals from daily to weekly. However, no alternative regimen is specified for MJ7/18 in the search results, which suggests this dose is a community standard.
• For in vitro or ex vivo applications (e.g., flow cytometry, IHC, immunofluorescence), recommended concentrations are much lower, generally in the range of 2–5 μg/mL for staining.

Additional notes:

• MJ7/18 is a rat IgG2a monoclonal antibody targeting mouse endoglin (CD105), primarily used for tumor angiogenesis studies and endothelial cell identification.
• No published data in the search results describe variations due to different strains, ages, or co-morbid conditions in mice, nor adaptations for non-tumor models.
• Pharmacodynamic monitoring may be necessary to adjust the dosing for specific endpoints, but 100 μg every other day provides both efficacy and safety in published tumor model studies.

In summary:
The standard in vivo dosing regimen for clone MJ7/18 in published mouse model research is 100 μg/mouse i.p. every other day, especially for tumor models; in vitro uses require much lower concentrations. There is no evidence in the current search results of significant variation across mouse models.