Anti-Human CD119 (IFN-γ Rα Chain) – Purified in vivo GOLD™ Functional Grade

Clone GIR-208 is most commonly used in vivo in mice as an isotype control antibody, especially in studies involving type I or type II interferon signaling. GIR-208 recognizes human IFN-γ receptor alpha but does not interact with mouse interferon-gamma receptors, making it suitable as a negative control for specificity assessments in mouse models.

Key in vivo applications in mice include:

• Isotype control: In immunological studies, particularly where other antibodies (such as anti-mouse IFNAR1 clone MAR1-5A3) are used to block cytokine signaling, GIR-208 is administered to control for nonspecific effects of antibody injection.
• Functional assays: GIR-208 can serve as an isotype control in functional experiments to verify that observed effects are due to specific antibody-target interactions rather than nonspecific immune modulation.
• Negative control in infection models: GIR-208 is used as a comparator in viral or infectious disease mouse models. For example, in studies of dengue virus infection, mice treated with GIR-208 showed no weight loss or clinical signs, and tissues tested negative for viral RNA, confirming its role as an inert control compared to disease-modifying antibodies.

Important context:

• Does not block mouse cytokine receptors: GIR-208 specifically binds human IFN-γ receptor alpha, and does not bind or block the analogous mouse receptor. This property explains its use exclusively as a negative control, rather than as a functional or therapeutic antibody in mice.
• Recommended pairings: GIR-208 is often used alongside clone MAR1-5A3, a functional anti-mouse IFNAR1 antibody, allowing distinction between isotype effects and true cytokine blockade in murine systems.

Summary of typical use:

• GIR-208’s primary in vivo role in mice is as a negative/isotype control to validate findings of specificity and rule out off-target or non-specific antibody effects within immunological and infectious disease models. It is not used therapeutically or diagnostically in mouse models because of its lack of reactivity with mouse IFN-γ receptors.

Commonly used antibodies or proteins with GIR-208 (anti-human CD119, IFNγ receptor alpha) in the literature include other antibodies targeting the interferon-gamma signaling pathway, with GIR-301 and isotype controls such as MOPC-21 being the most frequently mentioned companions.

Key details include:

• GIR-301: This is another monoclonal antibody against a component of the IFN-γ receptor complex and is often paired with GIR-208 in functional studies to compare or validate results within the IFN-γ signaling context.
• Isotype control antibodies: Controls such as Mouse IgG1, κ (e.g., MOPC-21) are important for ensuring specificity in flow cytometry and immunoassays when using GIR-208.
• Recombinant human IFN-γ protein: Sometimes used in competition experiments to validate GIR-208 binding specificity, since excess IFN-γ can inhibit GIR-208 binding to CD119.
• Other IFN-γR antibodies: Studies recommend using non-neutralizing antibodies against IFN-γRα (different clones, such as PE Mouse Anti-Human CD119, Cat. No. 558937) for detection in scenarios where GIR-208's neutralizing function may mask epitope recognition.

Typical experimental contexts for combining these reagents:

• Flow cytometry and immunofluorescence to detect IFN-γRα (CD119) expression, using isotype controls and sometimes fluorophore-conjugated secondary antibodies as well.
• Functional blocking assays, often combining GIR-208 with other IFN-γ pathway blockers or agonists.
• Western blotting and ELISA, sometimes utilizing a combination of GIR-208, non-neutralizing anti-CD119 antibodies, or detection antibodies for IFN-γ itself.

In summary, GIR-301, isotype controls (like MOPC-21), and recombinant IFN-γ protein are the most commonly used reagents alongside GIR-208 in published literature surrounding IFN-γ receptor studies.

Key findings from scientific literature citing clone GIR-208 focus on its use as a research tool targeting the human interferon-gamma receptor 1 (IFNγR1 or CD119), primarily as an isotype control to ensure experimental specificity and validity.

Essential findings include:

• Clone GIR-208 is widely used as an isotype control antibody in both in vitro and in vivo experiments to rule out non-specific or off-target effects when studying interferon signaling, especially in mouse models where GIR-208 itself does not block murine interferon signaling.
• GIR-208 specifically recognizes human IFNγRα (CD119), which is a key component of the IFNγ receptor complex involved in JAK-STAT signaling. This makes it suitable for flow cytometry, functional assays, and as a control in experiments manipulating interferon pathways.
• It is reported for use in flow cytometric analysis and functional assays to confirm antibody specificity in experimental immunology.
• The antibody does not bind when IFNγ is already engaged to its receptor, and expression of the receptor is generally ubiquitous but low, with higher expression on certain immune cell subsets, such as monocytes.

Experimental context and supporting detail:

• GIR-208 has been specifically cited as an isotype control in studies using anti-mouse IFNAR1 (clone MAR1-5A3) to discern effects of Type I interferon blockade.
• It is highlighted in translational models, such as C57BL/6J mice challenged with viral pathogens, to demonstrate that observed effects are due to specific antibody blockade rather than nonspecific immunoglobulin effects.
• The antibody is recommended to be carefully titrated for each application, with commonly cited concentrations for flow cytometry (≤0.5 μg per 10^6 cells).

In summary:

• GIR-208 is integral for experimental controls in interferon signaling research due to its specificity for human IFNγR1 and lack of blocking activity in murine systems, thereby allowing robust discrimination between specific and nonspecific antibody effects in immunological assays.
• No primary literature describes GIR-208 as an antagonist or therapeutic; its scientific utility lies in experimental controls and assay validation.

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Dosing Regimens of Clone GIR-208 in Mouse Models

Standard Approach Across Models

The dosing regimen for clone GIR-208, an anti-human IFNγ receptor (CD119) monoclonal antibody used as an isotype control in many experiments, is notably consistent across various mouse models and experimental conditions. The established protocol is a single intraperitoneal (i.p.) injection of 2 mg per mouse, administered one day before the experimental intervention. This dose and route are widely referenced in the literature, with no evidence of substantial variation between different mouse strains, disease models, or experimental contexts.

Published Examples and Model Variability

Several published studies specifically use this dosing regimen in C57BL/6J mice, a common wild-type background in immunology research. For example, a study comparing immune responses in the context of viral infection treated C57BL/6J mice with a single 2 mg dose of GIR-208, observing no significant adverse effects or deviation from the standard protocol. Another publication confirms the use of this isotype control at the same fixed dose, with no mention of strain-specific adjustments. Some studies have tested a lower dose (0.2 mg) in wild-type mice, but this appears to be an exception rather than a routine variation.

Absence of Dose Titration or Multi-Dose Regimens

Unlike therapeutic or depleting antibodies (e.g., anti-PD-1, anti-CD4, anti-CD8), where dosing frequency and amount may be titrated based on target, model, or desired effect, GIR-208 is used almost exclusively as a single-dose, fixed-concentration isotype control. There is no evidence of repeated dosing, dose escalation, or model-specific dose adjustments for GIR-208 in the available literature. The simplicity and consistency of this regimen reflect its role as a negative control rather than an experimental variable.

Summary Table

Conclusion

The dosing regimen for clone GIR-208 in mouse models is highly consistent: a single 2 mg i.p. injection administered one day prior to experimental intervention, regardless of mouse strain or disease model. Significant variation across models has not been reported, and dose titration or multi-dose regimens are not part of standard practice for this isotype control.