Anti-Mouse Delta-like protein 4 (DLL4) – Purified in vivo PLATINUM™ Functional Grade

Common In Vivo Applications of Clone HMD4-2 in Mice

Clone HMD4-2 is a hamster-derived monoclonal antibody that specifically targets mouse Delta-like protein 4 (DLL4), a key ligand in the Notch signaling pathway. DLL4 is primarily expressed by vascular endothelial cells and plays a crucial role in regulating angiogenesis, especially during development and in pathological conditions such as cancer. Below are the principal in vivo applications of HMD4-2 in mouse models, based on current literature and commercial usage.

Inhibition of DLL4 Signaling in Cancer Models

• Tumor Angiogenesis and Growth Inhibition: Intraperitoneal administration of HMD4-2 has been shown to suppress in vivo tumor growth in mouse models. This effect is mediated by a marked decrease in tumor vasculature, as DLL4 blockade disrupts productive angiogenesis, leading to the formation of non-functional, poorly perfused blood vessels that compromise tumor growth.
• Mechanism of Action: By neutralizing DLL4, HMD4-2 inhibits Notch signaling in endothelial cells, which is essential for the “tip cell” selection process during angiogenesis. Disruption of this process causes excessive, but ineffective, sprouting of blood vessels, thereby starving the tumor of nutrients and oxygen.
• Tumor Models: HMD4-2 has been evaluated in various cancer types where DLL4-mediated angiogenesis is implicated, such as clear-cell renal, pancreatic, bladder, and colonic cancers. However, the antibody does not directly inhibit tumor cell proliferation, acting instead through the tumor vasculature.

Additional Research Context

• DLL4 Expression Regulation: DLL4 expression in endothelial cells can be upregulated by factors such as VEGF, bFGF, and HIF-1α, which are prominent in the tumor microenvironment. Consequently, HMD4-2 is used to study the interplay between these pathways and Notch signaling in vivo.
• Product Form and Administration: HMD4-2 is available as purified IgG suitable for in vivo use, typically administered via intraperitoneal injection. Its specificity for mouse DLL4 makes it a valuable tool for preclinical angiogenesis and cancer research in murine systems.
• No Direct Effect on Non-Endothelial Tissues: The primary biological effect of HMD4-2 is on the vascular endothelium. There is no evidence from the available sources that HMD4-2 affects other cell types or pathways outside the vasculature in vivo.

Summary Table: In Vivo Applications of HMD4-2

Key Points

• HMD4-2 is widely used to study the role of DLL4/Notch signaling in tumor angiogenesis and to evaluate therapeutic strategies targeting pathological angiogenesis in mice.
• Its main in vivo application is intraperitoneal administration to inhibit tumor growth by disrupting the tumor vasculature, rather than by direct antitumor effects.
• HMD4-2 is not used for immune humanization, gene therapy, or non-vascular biology in the context of current literature.

Limitations and Considerations

• Species Specificity: HMD4-2 is specific to mouse DLL4 and should not be expected to cross-react with human or other species’ DLL4.
• Administration Route: The standard route is intraperitoneal injection; other routes have not been widely reported for this clone.
• Scope of Effect: The antibody’s effects are confined to processes involving DLL4-expressing endothelial cells, particularly in the context of angiogenesis.

In conclusion, the most common and validated in vivo application of HMD4-2 in mice is the inhibition of DLL4-mediated angiogenesis, especially in cancer research, where it serves as a robust tool to study and modulate tumor vasculature.

Commonly used antibodies or proteins in the literature with HMD4-2 (anti-mouse Delta-like protein 4, DLL4) include markers and probes relevant to the Notch signaling pathway, endothelial cell identification, angiogenesis, and immune profiling controls.

Essential context and supporting details:

• Notch Pathway Proteins: HMD4-2 targets DLL4, a major Notch ligand. Experiments often co-stain for other Notch pathway components, including:

  • Notch receptors (Notch1, Notch4) to evaluate co-expression or pathway activation status.
  • Other Notch ligands such as Jagged1 or DLL1 for pathway comparison (though direct co-application with HMD4-2 must be confirmed in individual publications).

• Endothelial and Vascular Markers: Since DLL4 is endothelial-expressed, studies may use:

  • CD31 (PECAM-1) as a general vascular endothelial marker.
  • VE-cadherin (CD144) for vascular junction integrity.
  • VEGF and VEGF receptor 2 (KDR/Flk-1) to probe angiogenic signaling, as DLL4 expression can be upregulated by VEGF stimuli.
  • HIF1α when angiogenesis and hypoxic conditions are studied concurrently.

• Tumor or Developmental Markers: In tumor models or embryological angiogenesis studies, researchers may use:

  • Markers for different tumor cell lineages.
  • Proliferation/apoptosis markers (e.g., Ki67, TUNEL assay).

• Isotype Controls: Proper interpretation often requires controls such as:

  • Armenian hamster IgG isotype control (the isotype of HMD4-2).

• Buffer/Technical Controls:

  • Dilution buffers (e.g., phosphate-buffered saline, pH 7.0).

Additional relevant proteins:

• Basic-FGF: May be included in studies investigating DLL4 expression regulation.
• Other DLL4-targeting antibodies: For comparative or corroborative studies.

In summary, proteins and antibodies most often used alongside HMD4-2 are those involved in Notch signaling, endothelial cell identification, and relevant technical controls. When designing experiments or interpreting past studies, these are the primary co-reagents and targets reported in the literature.

The clone HMD4-2 is a hamster monoclonal antibody specifically designed to recognize mouse Delta-like protein 4 (DLL4), a crucial ligand in the Notch signaling pathway. DLL4 plays a significant role in vascular development and angiogenesis, and its blockade has been explored for its potential anti-tumor effects. Here are some key findings related to clone HMD4-2:

1. Role in Vascular Development and Angiogenesis: DLL4 is expressed by vascular endothelium and is vital for embryonic vascular development. It influences angiogenesis, particularly in the context of tumor growth, where its blockade can inhibit tumor progression by promoting non-productive angiogenesis.

2. Notch Signaling Pathway: As a ligand of the Notch pathway, DLL4's interaction with Notch receptors is crucial for cell differentiation and development. Its expression can be modulated by factors like VEGF and HIF1 alpha, which are involved in angiogenesis.

3. Hematopoiesis and Hematopoietic Stem Cells (HSCs): Studies have shown that DLL4 is involved in the self-renewal and proliferation of HSCs. However, systemic blockade of DLL4 does not impair HSC function but can enhance hematopoietic recovery in bone marrow transplantation settings by affecting the vascular niche.

4. Tumor Angiogenesis and Anti-Tumor Effects: DLL4 blockade has been explored as a therapeutic strategy to inhibit tumor growth by disrupting angiogenesis. This approach has shown promise in preclinical models and clinical trials for various cancers.

Overall, clone HMD4-2 provides a tool for studying DLL4's role in vascular biology and its potential applications in cancer therapy.

Currently, there is limited specific information available on how dosing regimens of the clone HMD4-2, an anti-mouse Delta-like protein 4 (DLL4) antibody, vary across different mouse models. The available literature does not provide detailed dose variation or specific regimens for HMD4-2 in different mouse models, such as immunocompetent versus immunodeficient strains.

However, general principles of antibody dosing in mouse models can be applied:

1. Dose Range: For many antibodies tested in mouse models, doses typically range from 100 to 500 μg per mouse, with specific dosages often determined based on the target's expression level and the model's sensitivity.

2. Route of Administration: Intraperitoneal (IP) or intravenous (IV) injections are common routes for antibody administration in mouse studies.

3. Dosing Schedule: The frequency of dosing can vary, often ranging from every 3 to 4 days for certain antibodies. However, specific schedules for HMD4-2 in various mouse models are not detailed in the current literature.

4. Pharmacokinetics: The pharmacokinetics of antibodies like anti-DLL4 can be dose-dependent and may vary between different mouse strains or models, affecting the choice of dosing regimen.

Without specific data on HMD4-2 dosing regimens across different mouse models, it is advisable to consult original research articles or conduct pilot studies to determine optimal dosing strategies for specific applications.