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

Clone HMD4-2 is most commonly used in vivo in mice to neutralize Delta-like protein 4 (DLL4), particularly for studying the effects of DLL4 blockade on angiogenesis and tumor growth.

Key in vivo applications include:

• Neutralizing DLL4 during tumor studies: HMD4-2 has been administered (typically by intraperitoneal injection) to block DLL4-mediated Notch signaling, inducing non-productive angiogenesis and suppressing tumor growth in murine models of cancers such as renal cell carcinoma, pancreatic, bladder, and colon tumors.
• Angiogenesis modulation: Since DLL4 is a critical regulator of vascular development and angiogenesis, in vivo administration of HMD4-2 is used to investigate the vascularization process, including developmental, pathological (e.g., cancer), and therapeutic angiogenesis.
• Functional studies of the Notch pathway: By specifically inhibiting DLL4, researchers use HMD4-2 to dissect DLL4’s role within the Notch signaling axis in endothelial cell biology and related physiological or pathological processes.

Supporting details:

• The antibody is validated for in vivo neutralization and “DLL4 neutralization” is listed as its application in major antibody registries and supplier descriptions.
• Experimental protocols report dosing via intraperitoneal injection, with outcomes including reduced tumor vasculature and impaired tumor growth in treated mice, without direct effect on the cancer cells themselves.
• Researchers also employ HMD4-2 for mechanistic studies of DLL4 in up-regulation scenarios (e.g., response to VEGF or hypoxia).

Summary of principal in vivo uses:

• Tumor angiogenesis blockade
• Vascular development research
• Cancer progression studies (via Notch pathway manipulation)
• Functional DLL4/Notch pathway dissection in mammalian models

No evidence was found for routine use of this clone in immunohistochemistry or flow cytometry in tissue slices from in vivo experiments—its primary application is acute DLL4 neutralization in living mice.

In the literature, while HMD4-2 is specifically mentioned as an antibody targeting mouse Delta-like protein 4 (DLL4), other commonly used antibodies or proteins that might be used in conjunction with or discussed alongside DLL4 or Notch signaling pathway components include:

1. Anti-Notch1, Anti-Notch2, Anti-Notch3, and Anti-Notch4 Antibodies: These are crucial for studying the Notch signaling pathway, which DLL4 is a part of. These antibodies would be used to investigate the broader context of Notch signaling in vascular development and cancer.

2. VEGF and FGF Antibodies: Given that vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF) upregulate DLL4 expression, antibodies targeting these proteins could be used to study angiogenesis and tumor growth.

3. HIF1α Antibodies: Hypoxia-inducible factor 1 alpha (HIF1α) is involved in the regulation of DLL4 expression. Antibodies against HIF1α would help in understanding how hypoxic conditions influence DLL4 signaling.

In terms of proteins, studies involving DLL4 often consider the role of other Notch ligands like Jagged1 and Jagged2. These proteins are involved in similar signaling pathways and their interactions with DLL4 can provide insights into broader Notch signaling dynamics.

For specific antibodies mentioned in the context of engineered ADCs targeting DLL4, such as HLmD4 and HLvM4, they are site-specific antibody-drug conjugates used in therapeutic studies against DLL4-positive tumor models. However, these are not commonly paired with HMD4-2 in the literature but are relevant to DLL4 research.

Lastly, while not directly mentioned with HMD4-2, B4-IgM and other antibodies like those targeting H3K4me3 are involved in distinct research contexts but show the diversity of antibodies used in various biological studies.

The key findings from scientific literature using clone HMD4-2 focus on its role as a monoclonal antibody targeting mouse Delta-like protein 4 (DLL4), a critical ligand of the Notch signaling pathway predominantly expressed in vascular endothelium.

Key findings include:

• Characterization and Specificity: Clone HMD4-2 is a hamster-derived IgG antibody that specifically recognizes mouse DLL4, allowing precise interrogation of DLL4 functions in various biological contexts, especially in vascular and tumor biology.

• Role in Angiogenesis: DLL4 signaling is crucial for angiogenesis (the growth of new blood vessels), both under physiological conditions and in tumors. Inhibition or blockade of DLL4—using antibodies like HMD4-2—leads to disruption of normal vessel formation, typically resulting in abnormal, non-productive angiogenesis. This has been proposed as a strategy to restrict tumor growth by altering the tumor vasculature.

• Hematopoietic Effects: In vivo studies using anti-DLL4 (including HMD4-2 or functionally analogous antibodies) show that systemic blockade does not impair hematopoietic stem/progenitor cell (HSPC) phenotype or function. However, anti-DLL4 treatment in bone marrow transplant settings has been observed to marginally accelerate hematopoietic recovery, likely by affecting bone marrow endothelium and enhancing stem cell homing and engraftment. DLL4 blockade was also associated with increased expression of vascular markers such as CD31 and VE-Cadherin in the bone marrow, potentially facilitating improved vascular support for hematopoiesis.

• Tumor Biology: DLL4 inhibition affects tumor vascularization and growth in several cancer models, including clear cell renal, pancreatic, bladder, and colon cancers, making anti-DLL4 antibodies like HMD4-2 valuable research tools for preclinical anti-angiogenic therapy studies.

• Notch–DLL4 Pathway Modulation: Notch receptor signaling, modulated through DLL4 and its ligands, is an essential regulator of vascular development and is upregulated by cues such as VEGF, basic FGF, and HIF1α.

• Use in Flow Cytometry and Tissue Staining: HMD4-2 is commonly validated for flow cytometry and immunohistochemistry, aiding in delineating the expression and functional activity of DLL4 in both normal and pathological tissues.

No direct conflicts in the literature were identified regarding the function of HMD4-2 as a DLL4-specific antibody, though some studies highlight that the in vivo vascular and hematopoietic effects of DLL4 inhibition can be context- and cell-dependent, warranting precise interpretation of results depending on the experimental design.

Summary Table: Clone HMD4-2 in Scientific Literature

Overall, clone HMD4-2 has become a foundational research tool enabling detailed dissection of DLL4 biology, particularly within vascular and tumor models.

Based on currently available information, no dose variation or specific regimen for HMD4-2 is described between different mouse models, such as immunocompetent versus immunodeficient strains. The literature does not provide detailed comparative data on how dosing protocols for this anti-mouse Delta-like protein 4 (DLL4) antibody should be adjusted across different mouse model systems.

What We Know About HMD4-2

Clone HMD4-2 is an Armenian hamster anti-mouse Delta-like protein 4 (DLL4) monoclonal antibody. DLL4 is one of the five major ligands of the Notch signaling pathway and is expressed by vascular endothelium, playing a vital role in embryonic vascular development. The protein has been shown to play a role in angiogenesis of various cancers, including clear-cell renal tumors and pancreatic, bladder, and colonic cancer.

Gap in Dosing Information

While comprehensive dosing guides exist for other commonly used in vivo antibodies in mouse models—such as checkpoint blockade antibodies (anti-PD-1, anti-PD-L1, anti-CTLA-4) and immune cell depleting antibodies (anti-CD4, anti-CD8)—with standard dose ranges typically between 100-500 μg per mouse depending on the specific antibody, precise dosing regimens for clone HMD4-2 across different mouse models are not currently documented in available sources.

This absence of standardized protocols means that researchers working with HMD4-2 would need to empirically determine appropriate dosing for their specific experimental conditions or rely on unpublished protocols from other laboratories.