Anti-Human/Mouse Integrin β7 – Purified in vivo GOLD™ Functional Grade

Clone FIB504 is primarily used in in vivo mouse studies to block β7 integrin-mediated cell adhesion, allowing researchers to investigate the role of β7 integrin in immune cell migration, tissue homing, and inflammatory responses.

This antibody, which specifically binds to mouse (and human) integrin β7, is administered to mice to inhibit integrin β7 function. Blocking integrin β7 impairs the interaction of immune cells—such as lymphocytes and certain T cell subsets—with endothelial and tissue ligands, thereby affecting cellular trafficking and localization during immune and inflammatory processes. The antibody can be used to explore mechanisms of immune cell recruitment to specific tissues such as the gut, as integrin β7 is important for homing to mucosal sites.

Key in vivo applications include:

• Functional blocking studies: FIB504 is administered to living mice (intravenously or intraperitoneally) to block integrin β7 on circulating immune cells, disrupting migration and adhesion to target tissues, such as during models of colitis or infection.
• Investigating disease mechanisms: By blocking β7 integrin, researchers can determine the contribution of β7-mediated pathways in disease settings, including inflammatory bowel disease and immune cell trafficking.
• Cell adhesion inhibition assays: FIB504 can also be used to confirm target engagement, for example showing inhibited lymphocyte adhesion to ligands such as MAdCAM-1, fibronectin, or VCAM-1 in ex vivo and in vivo scenarios.

Additional experimental uses:

• The antibody is used in flow cytometry and immunohistochemistry to detect integrin β7 expression, but in vivo studies primarily leverage its blocking activity.

In summary, FIB504 enables targeted inhibition of β7 integrin in living mice, yielding insights into immune cell migration, inflammatory pathways, and tissue-specific homing by preventing integrin β7-dependent cell adhesion.

Commonly used antibodies and proteins paired with FIB504 (anti-integrin β7 monoclonal antibody) in the literature include antibodies to cell surface markers such as CD3, isotype controls, and fluorescently labeled secondary antibodies; additionally, anti-integrin α4 (ITGA4) and proteins recognizing the integrin heterodimer (α4β7) are frequently utilized as comparators or in functional studies.

Key commonly used antibodies or proteins:

• Anti-CD3 antibodies: Frequently used to distinguish T cell subsets in flow cytometry when analyzing integrin β7 expression. For example, mouse splenocytes are stained with FIB504 (anti-β7) and then with anti-CD3 conjugated to Alexa Fluor® 647 to gate on T cells.
• Secondary antibodies: Such as goat anti-rat IgG (e.g., Alexa Fluor® 488-conjugated) are used for detection when FIB504 is unconjugated or biotinylated.
• Isotype controls: Typically, a rat IgG2a isotype control antibody, matched to FIB504's isotype, is used as a negative control in flow cytometry or immunostaining to ensure specificity.
• Anti-integrin α4 (ITGA4) antibodies: The integrin β7 pairs with α4 (as α4β7, also called LPAM-1) or αE (as αEβ7, HML-1), and studies often use anti-α4 or anti-αE alongside anti-β7 (FIB504) to distinguish these integrin heterodimers and their functional interactions.
• MAdCAM-1 (mucosal addressin cell adhesion molecule 1): This is the main ligand for α4β7 integrin and is sometimes used as a recombinant protein in binding assays or functional studies.
• Other V2 domain-specific antibodies: In competitive binding and functional blockade studies, FIB504 is used alongside multiple anti-gp120 V2 domain monoclonal antibodies such as 1019, 1027, 1017, 1022, 1028, 1029, 1088, 1025, and 6E10, particularly in research related to HIV-1 entry and immune evasion.

Summary Table: Common Antibodies/Proteins Used with FIB504

When designing experiments with FIB504, the use of anti-CD3, isotype controls, and secondary antibodies is standard for lymphocyte phenotyping by flow cytometry, while anti-α4 and relevant recombinant ligands/proteins are important for functional and comparative studies.

Key findings from scientific literature citing clone FIB504 center on its role as a monoclonal antibody specifically targeting the integrin β7 subunit and its broad application in immunological research and imaging.

• Target specificity and cross-reactivity: Clone FIB504 is a monoclonal antibody that recognizes the mouse integrin β7 subunit and also cross-reacts with human integrin β7, making it valuable for flow cytometry analyses of lymphocytes and studies in both human and mouse systems.

• Imaging of intestinal inflammation: FIB504, when radiolabeled (e.g., with ^64Cu), enables noninvasive imaging and detection of gut inflammation (colitis) in animal models. Studies using microPET imaging in mice demonstrated significantly higher uptake of ^64Cu-labeled FIB504 in the inflamed intestines of colitis models compared to controls, supporting its potential as a tool for radioimmunodetection of inflammatory bowel disease and guiding diagnosis and therapy.

• Antibody development and humanization: FIB504 is the parent antibody from which the humanized monoclonal antibody rhuMAb Beta7 was derived for therapeutic purposes. Development efforts revealed that restoring antigen binding required specific framework and CDR (complementarity-determining region) repairs when converting FIB504 to a humanized form, highlighting the importance of both variable and constant regions in antibody engineering.

• Functional studies and disease models: While anti-β7 antibodies derived from FIB504 (e.g., muFIB504) have been tested in models of inflammatory diseases such as experimental autoimmune encephalomyelitis (EAE) and colitis, results indicate selective effectiveness: anti-β7 did not reduce CNS inflammation or disease severity in EAE, whereas anti-α4 antibodies did, underscoring differing immunological roles for these integrins in disease biology.

In summary, clone FIB504 is widely used to probe integrin β7 expression and function, to facilitate imaging of gut inflammation, and to serve as a starting point for developing therapeutic antibodies targeting this integrin in various preclinical and translational research contexts.

Dosing regimens of clone FIB504 (anti-β7 integrin antibody) in mouse models can vary depending on the specific experiment and mouse strain, but published studies provide some representative details.

• In a single-dose distribution study using normal female BALB/c mice (18–21 g), a single intraperitoneal (i.p.) bolus dose of anti-β7 (muFIB504) was administered.
• In an experimental autoimmune encephalomyelitis (EAE) model, mice received anti-β7 (muFIB504) doses, but the study found it had no significant effect on disease severity or central nervous system inflammatory infiltration compared to anti-α4 antibody.

Additional dosing guides for similar monoclonal antibody treatments in mice suggest that effective doses for in vivo studies typically range between 100–500 µg per mouse per dose (for standard antibody clones targeting immune checkpoints), given intraperitoneally (i.p.). Frequency of dosing often ranges from every 3 to 4 days, but specific regimens for FIB504 were not detailed in general antibody dosing guides.

Key points:

• Dose: Most studies utilize single i.p. bolus doses, often around 5 mg per mouse for initial distribution studies.
• Route: Intraperitoneal injection is the standard administration method.
• Frequency: Published robust dose schedules for FIB504 remain rare; other antibodies targeting similar immune pathways use schedules of every 3–4 days.

Dosing regimens may change if different mouse models are used (e.g., disease-specific strains, variations in body weight, or immune status), but specific comparative data for FIB504 across mouse models, aside from BALB/c, is currently limited in the publicly available literature.

If the goal is to design an experiment using FIB504 in a new mouse model, it would be prudent to start with single doses around 5 mg per mouse, i.p., as in the BALB/c study, while considering adjustments based on body weight or disease context. Always check for updated literature and pilot dosing studies to fine-tune for specific models and endpoints.