Anti-Human Fibulin-4 [Clone 5G11] — Purified in vivo GOLD™ Functional Grade

Clone 5G11 has several distinct applications in mouse research, though it's important to note that this clone designation refers to different antibodies targeting different proteins. The most prominent in vivo application involves the lymphotoxin beta receptor (LTβR), while other 5G11 clones target human proteins for ex vivo or in vitro studies.

LTβR Research

The primary in vivo application of clone 5G11 in mice involves studying the lymphotoxin beta receptor. This rat monoclonal antibody specifically recognizes mouse LTβR, a member of the tumor necrosis factor receptor superfamily expressed mainly on stromal cells and fibroblasts. The 5G11 antibody functions as an agonistic antibody that can activate LTβR and induce NFκB activation, making it a valuable tool for investigating LTβR signaling pathways.

LTβR plays a critical role in peripheral lymphoid tissue organogenesis and function, and the LTα/LTβR receptor system may also have functions in early embryogenesis. In vivo studies have utilized this system to investigate inflammatory diseases, as LTβR regulates immune cell trafficking and communication. Research has demonstrated that deficiency in LTβR can protect mice from atherosclerosis, highlighting the receptor's importance in cardiovascular disease models.

Disease Model Applications

The antibody is employed in mouse models to study immune-mediated conditions. For instance, in inflammation research, the LTβR pathway has been investigated using mouse models where manipulation of this receptor system helps elucidate mechanisms of inflammatory disease progression and resolution.

It's worth noting that other antibodies sharing the 5G11 clone designation target human-specific proteins like desmoglein-3 and fibulin-4, but these are not typically used for in vivo mouse studies since they recognize human rather than mouse antigens.

The antibody 5G11 is used in the literature for at least three different targets (LTβR, Fibulin-4, and Desmoglein 3), so the context of its application matters. Commonly used co-antibodies or proteins depend on the target:

1. 5G11 for LTβR (Lymphotoxin Beta Receptor)

Frequently used with:

• Ligands: Lymphotoxin-α1β2 (LTα1β2) and LIGHT, which naturally activate LTβR.
• Cytokine markers: IFN-β, MIP-2, IL-6, and IFN-γ are often assayed to measure activation of LTβR signaling.
• Cell-type markers: Fibroblast and stromal cell markers, sometimes B cell and myeloid cell markers.
• NF-κB pathway proteins: Proteins involved in downstream signaling, such as p65 (RELA).
• Immune cell markers: For example, CD3 or CD4 for T cells, B220 for B cells.

Secondary antibodies:

• Commonly Mouse IgG-specific anti-mouse secondary antibodies.

2. 5G11 for Desmoglein 3

Frequently used with:

• Other desmoglein antibodies: Antibodies against Desmoglein 1 or 2 to distinguish between isoforms.
• Epithelial cell markers: Such as cytokeratins (e.g., K14, K5), to define cell types in skin or cancer studies.
• Adhesion/junctional proteins: Anti-E-cadherin or anti-plakoglobin, for mapping cell junction complexes.
• Tumor markers: For example, p63 in squamous cell carcinoma research.
• F-actin: Via phalloidin staining to examine cytoskeletal organization with Desmoglein 3.

3. 5G11 for Fibulin-4

Frequently used with:

• Other ECM proteins: Antibodies against other fibulins (Fibulin-1, -2, or -5), elastin, or collagen to examine extracellular matrix composition in tissues.
• Smooth muscle cell or fibroblast markers: For vascular or connective tissue studies.
• Endothelial markers: CD31/PECAM-1 or von Willebrand factor, if examining vasculature.

General Proteins and Reagents

• Secondary antibodies: Goat anti-mouse or anti-rabbit IgG conjugated to HRP, Alexa Fluor, or other detection systems are routinely used.
• Loading controls: In western blots, proteins like β-actin, GAPDH, or tubulin.
• Bacterial IgG-binding proteins: Protein A, G, or L, for antibody purification or detection in various assays, especially with mouse or rabbit antibodies.

Note on Nomenclature:
"5G11" refers to the clone and is used by different suppliers for different targets (LTβR, Desmoglein 3, Fibulin-4, TOPORS). The proteins/antibodies used with it must be chosen according to experimental context.

Summary Table: Commonly Used Antibodies/Proteins with 5G11 by Target

If you have a specific target in mind for your 5G11 antibody, more precise combinations can be suggested.

Clone 5G11 represents two distinct monoclonal antibodies that have made significant contributions to research in different fields. The key findings vary depending on which antibody is being referenced.

Anti-Desmoglein 3 (DSG3) Antibody

The most extensively documented clone 5G11 is a mouse monoclonal antibody targeting human desmoglein 3, a critical protein in epithelial cell adhesion. This antibody has been instrumental in pemphigus vulgaris research and desmosome biology.

Non-Pathogenic Binding Properties

A crucial finding is that clone 5G11 recognizes DSG3 without inducing the pathogenic effects seen in pemphigus vulgaris. Research demonstrates that this antibody exhibits calcium-independent binding to DSG3, distinguishing it from pathogenic anti-DSG3 autoantibodies that typically require calcium-dependent conformational epitopes. When engineered as a chimeric mouse IgG2a antibody (18-1m), it did not induce keratinocyte dissociation in cell-cell dissociation assays, whereas pathogenic control antibodies like AK23m did.

Epitope Mapping and Functional Studies

The binding region of clone 5G11 was mapped to cadherin domains outside of EC1, which explains its lack of pathogenic activity since disruption of EC1-EC2 domains typically causes loss of cell-cell adhesion. This specific binding profile makes it valuable for studying DSG3 localization and expression without interfering with normal desmosomal function.

Clinical Applications

Clone 5G11 has been extensively used to study DSG3 depletion patterns in pemphigus vulgaris patients, helping researchers understand disease mechanisms. The antibody recognizes the extracellular domain of the 130 kDa pemphigus vulgaris antigen and has proven effective in multiple techniques including immunohistochemistry, western blotting, and immunofluorescence.

Desmosome Research

Studies utilizing clone 5G11 have revealed insights into desmosomal adhesion mechanisms, including research showing that loss of flotillin expression results in weakened desmosomal adhesion and altered DSG3 localization similar to pemphigus vulgaris. The antibody has been critical for visualizing DSG3 synthesis patterns in basal and lower suprabasal layers of skin.

Anti-Lymphotoxin Beta Receptor (LTβR) Antibody

A separate clone 5G11 targets the lymphotoxin beta receptor in mice, contributing to understanding of peripheral lymphoid tissue development and immune cell interactions.

The dual identity of clone 5G11 underscores the importance of specifying the target antigen when citing this clone designation, as the two antibodies serve entirely different research purposes in epithelial biology versus immunology.

Dosing regimens of clone 5G11 (a mouse anti-human desmoglein 3 antibody) vary notably depending on the specific application and genetic background of the mouse model, but standardized, model-dependent dosing protocols are not established in the literature. Typically, the choice of dose, frequency, and administration route is tailored to experimental goals, such as histological staining, antibody-mediated disease modeling, or in vivo functional studies.

Essential context and supporting details:

• Model dependency: Dosing for clone 5G11 is primarily adjusted based on the mouse model's characteristics and the intended in vivo or ex vivo application. For example, transgenic mice engineered to express human desmoglein-3 may require different doses compared to wild-type mice due to differential antigen availability or immune responses.
• Lack of universal protocols: Unlike some commonly used depleting or checkpoint antibodies (such as anti-CD4, anti-CD8, anti-PD-1), there are no standardized published dose-and-schedule regimens specific to 5G11 across mouse models. The general approach is empirical, often derived from pilot titration or informed by similar monoclonal antibody studies in mice.
• Typical dosing practice: For in vivo functional studies—such as mouse models of pemphigus vulgaris—antibody doses for similar monoclonals can range from 1 to 8 mg total IgG per mouse, usually delivered as a single injection followed by tissue collection within 24 hours. However, these figures are provided for total IgG and not specifically for 5G11, which is primarily validated for detection applications rather than direct pathogenic modeling.
• Application dependence: 5G11 is most commonly used in immunohistochemistry or western blotting to detect desmoglein-3, where the dose relates to staining sensitivity rather than in vivo pharmacodynamics. Applications requiring disruption of Dsg3 function or induction of disease phenotypes would require separate validation and titration.
• Genetic background: Studies using mouse models expressing human DSG3 (either transgenics or knock-in mice) adjust antibody dosing to maximize binding and immunoreactivity without causing off-target effects.

Summary Table: Dosing Considerations for 5G11

Key insight: For clone 5G11, unlike many therapeutic or cell-depleting antibodies, dosing is usually determined case by case, and published literature lacks universally accepted regimens for specific mouse models. In all cases, empirical optimization is required.

If you need guidance for a particular experiment or disease model (e.g., pemphigus vulgaris modeling, histology, antibody blocking), specifying the goal will allow for more tailored recommendations.