Anti-Mouse CD32/CD16 [Clone 2.4G2] — Purified in vivo GOLD™ Functional Grade

Clone 2.4G2 is primarily used in vivo in mice as an antibody to block Fc gamma receptors CD16 (FcγRIII) and CD32 (FcγRII), thereby preventing non-specific binding of experimental antibodies and modulating immune responses.

Common in vivo applications include:

• Fc receptor blockade: 2.4G2 is administered to mice to block FcγRII and FcγRIII on immune cells (such as B cells, NK cells, macrophages, granulocytes, mast cells, and dendritic cells) during studies of antibody-mediated immune responses, reducing artifacts due to non-specific Fc binding.
• Flow cytometry and immunofluorescence: Used to block Fc receptors in vivo before harvesting tissues for flow cytometry or fluorescence-activated cell sorting, improving the specificity and accuracy of immune cell labeling.
• Functional immunological assays: Applied to neutralize endogenous Fc receptor activity in studies of biological pathways, such as those investigating phagocytosis, antibody-dependent cell-mediated cytotoxicity (ADCC), and antigen uptake by dendritic cells.
• Prevention of interference in bioanalytical assays: Employed during pharmacokinetic (PK) and anti-drug antibody (ADA) studies to avoid interference from mouse endogenous Fc receptor activity.

Dosage and administration:

• Pre-treatment often involves a single intraperitoneal injection, with 500 µg per mouse being a common dose, typically administered 24 hours before experimental challenge or antigen exposure.

Limitations:

• 2.4G2 does not block all mouse Fcγ receptors; for example, FcγRIV is not effectively blocked, so additional antibodies might be required for comprehensive Fc blockade.
• There can be some non-specific reactivity via its own Fc domain to FcγRI (CD64) in certain contexts, requiring careful experimental design.

Summary table:

2.4G2 is considered a standard tool for Fc receptor research in mouse immunology.

Commonly used antibodies and proteins paired with 2.4G2 (anti-mouse CD16/CD32) in the literature include cell surface marker antibodies for multiparameter flow cytometry—specifically B220, CD3, CD19, CD11b, Gr1, and NK1.1. These combinations enable precise immune cell phenotyping by blocking nonspecific Fc receptor-mediated antibody binding.

Most frequently co-used antibodies/proteins:

• B220: Marker for B cells
• CD3: T cell marker
• CD19: B cell marker
• CD11b: Myeloid cell marker (macrophages, monocytes, some dendritic cells)
• Gr1: Granulocyte marker
• NK1.1: Natural Killer cell marker

Other frequent combinations and controls:

• Isotype controls: Mouse IgG2a or irrelevant IgGs, to assess specificity
• Secondary antibodies: Anti-IgG antibodies for detection (avoiding anti-rat IgG2b, which may cross-react with 2.4G2)
• Fc receptor-related reagents: Fc fragments or complement proteins for assays validating Fc receptor blockade
• Anti-mouse kappa chain (e.g., clone 187.1): Used in some protocols for B cell identification when co-staining with 2.4G2

Technical practices:

• 2.4G2 is almost always used as an Fc receptor blocking reagent prior to staining to prevent non-specific Fc-mediated binding of other monoclonal antibodies, especially when analyzing immune cells that naturally express high levels of Fc receptors (macrophages, granulocytes, dendritic cells, NK cells).

Detection and analysis applications:

• Flow cytometry
• Immunofluorescence
• Occasionally, other applications such as immunoprecipitation, immunohistochemistry, and western blotting, depending on the needs of the study.

Researchers may also use other Fc receptor-blocking antibodies, such as clone 93, though it is distinct from 2.4G2 and not interchangeable in all experiments.

Summary Table:

In summary, 2.4G2 is typically used in combination with a broad set of lineage-defining antibodies and appropriate controls in multiparametric mouse immunophenotyping and functional immune assays, with attention to the technical details needed to ensure specific and accurate results.

Clone 2.4G2 is a monoclonal antibody extensively cited in scientific literature for its role as a blocker of mouse Fc gamma receptors II and III (FcγRII/CD32 and FcγRIII/CD16). Its key findings and uses include:

• Primary Application as Fc Blocker: 2.4G2 is widely used in mouse immunology experiments, particularly in flow cytometry and immunofluorescence. It is routinely applied to block FcγRII and FcγRIII on mouse immune cells, which prevents non-specific binding of other antibodies via their Fc regions—thereby increasing the specificity and accuracy of immunoassays.

• Specificity and Considerations: 2.4G2 binds a nonpolymorphic epitope on the extracellular domains of mouse CD16 and CD32. Some studies have reported non-specific interactions with FcγRI (CD64) when the antibody is bound to its primary targets, demanding caution in interpretation.

• Cell Types Targeted: CD16 and CD32 are expressed on several mouse immune cell types, including B cells, NK cells, macrophages, granulocytes, mast cells, and dendritic cells.

• Functional Research Applications:

  • 2.4G2 is used to study phagocytosis, antibody-dependent cell-mediated cytotoxicity (ADCC), and natural killer (NK) cell function, aiding in the dissection of Fc receptor-mediated pathways.
  • It is also used in in vivo settings to modulate immune responses by blocking activating and inhibitory FcγRs prior to immunological challenges or therapeutics.

• Standardization and Benchmarking: The 2.4G2 clone is regarded as a standard reagent for Fcγ receptor research, serving as a benchmark in hundreds of publications focusing on mouse immune cell phenotyping and function.

• Experimental Protocols: Typical dosing for in vivo receptor blockade cited in literature is 500 µg per mouse via intraperitoneal injection, usually administered 24 hours prior to antigen exposure or experimental manipulation.

• Limitations: 2.4G2 does not block all mouse Fcγ receptors. For example, it does not effectively block FcγRIV, so experiments targeting all subclasses may require additional reagents. Also, care is needed to avoid using anti-rat IgG2b secondary antibodies for detection, as 2.4G2 is a rat IgG2b isotype which could cross-react and cause misleading results.

• Demonstrated Specificity: Studies confirm that 2.4G2 binds FcγRIIB in wild-type but not Fcgr2b−/− animals, demonstrating specificity; it is used in precise gating and characterization of T-cell subpopulations expressing FcγRIIB.

• Innovative Formats: Derivatives such as single-chain Fv constructs from 2.4G2 have been developed for use in specialized cell marking and depletion experiments.

In summary, clone 2.4G2’s chief scientific value is its reproducible, efficient blockade of FcγRII and FcγRIII, minimizing non-specific antibody binding and enabling high-quality immunological research and functional studies in mice.

Dosing regimens of clone 2.4G2 (anti-mouse CD32/CD16) are largely standardized across different mouse models, most commonly employing a single 500 µg intraperitoneal (i.p.) injection 24 hours prior to experimental intervention. Significant variations in dose, schedule, or administration route are rare and not routinely reported in the literature.

Key details:

• Mouse strains (e.g., C57BL/6, BALB/c): The standard regimen—500 µg i.p., 24 hours before intervention—is applied across widely-used strains such as C57BL/6 and BALB/c mice.
• Timing: Injection is typically administered once, 24 hours in advance of experimental manipulation to allow effective FcγRII/RIII blockade.
• Dose adjustments: While the 500 µg dose is most prevalent, researchers may titrate the quantity based on unique experimental needs, mouse body weight, immune background, or to extend receptor blockade in chronic or repeated dosing studies.
• Administration route: Intraperitoneal administration is standard; alternative routes are rarely reported.
• Special cases: In scenarios involving different disease models or immunological backgrounds, some protocols may advise further titration, but published direct, model-specific dosing departures are minimal.

Summary dosing table for commonly used models:

Additional notes:

• Isotype controls (e.g., rat IgG2b) are recommended to control for non-specific effects in experiments using 2.4G2.
• Functional considerations: Blocking efficacy can vary based on Fcγ receptor expression profile in different strains or disease states, sometimes necessitating dosing adaptation for effective inhibition.
• Specialized research protocols (e.g., repeated or chronic dosing, pediatric models) may further modify the basic regimen, but such protocols are not routinely published and require primary literature or manufacturer guidance for details.

In summary, while minor adjustments may occur based on experimental nuance, clone 2.4G2 dosing is highly consistent across mouse models, with 500 µg i.p. 24h before intervention as the gold standard for acute receptor blockade.