Mouse IgG_2a Isotype Control [Clone C1.18.4] — Purified in vivo PLATINUM™ Functional Grade

Clone C1.18.4, a mouse IgG2a isotype control antibody, is commonly used in in vivo applications for several purposes:

1. Non-Specific Binding Control: It serves as a non-reactive isotype-matched control for mouse IgG2a antibodies, helping to account for non-specific binding in in vivo studies.

2. Flow Cytometry (FCM): Although primarily used for in vivo applications, its use in flow cytometry is noted for assessing non-specific binding to cells.

3. In Vivo Research: It is frequently used in mouse models to ensure that any observed effects are due to the specific antibody of interest rather than non-specific interactions.

4. Low Endotoxin Applications: Versions with low endotoxin levels are particularly beneficial for in vivo research, ensuring minimal inflammatory responses that could interfere with experimental results.

This antibody is often paired with antigen-specific IgG2a antibodies to provide a control for experiments, allowing researchers to distinguish between specific and non-specific binding effects.

C1.18.4 is a mouse IgG2a isotype control antibody used in immunological experimentsprimarily as a negative control. In the literature, it is commonly used alongside antibodies targeting specific antigens—especially other mouse IgG2a antibodies that target surface markers or immune-related proteins—to control for non-specific binding effects.

Commonly used antibodies or proteins with C1.18.4 include:

• Anti-MHC class I antibodies, such as 34-1-2S, SF1.1.10, and AF6-88.5. These are used to recognize mouse major histocompatibility complex (MHC) class I molecules in functional or mechanistic studies.
• Antibodies against cell surface markers (e.g., anti-CD antigens or other immunophenotyping markers) are often included in flow cytometry or in vivo studies, pairing C1.18.4 as the isotype control for proper background correction.

C1.18.4 itself is not used for detection of any specific cellular target but is co-applied as a control in experiments where specificity of mouse IgG2a-based detection or depletion antibodies may be in question. Its main role is to confirm that any observed effects are due to the target-specific antibody and not simply due to the IgG2a backbone or non-specific interactions.

Key pairings in published research include:

• Functional studies investigating complement activation use anti-MHC class I antibodies like 34-1-2S, SF1.1.10, and AF6-88.5, with C1.18.4 serving as the isotype control to validate specificity of observed immune effects.
• Immunophenotyping panels including protein markers such as T-bet or other lineage-specific antigens, often with the corresponding IgG2a isotype control run in parallel.

In summary, anti-MHC class I antibodies (e.g., 34-1-2S, SF1.1.10, AF6-88.5) and other cell surface marker antibodies are the most common antibodies used alongside C1.18.4 isotype control in immunological research.

Key Findings from Clone C1.18.4 Citations in Scientific Literature

Overview of Clone C1.18.4
The monoclonal antibody clone C1.18.4 (mouse IgG2a, κ isotype) is not subject to direct biological investigation in the literature but is instead extensively cited as a standard isotype control in immunological, oncology, and cell biology research. Its primary role is to assess nonspecific binding, providing a baseline for comparison with antigen-specific antibodies.

Primary Uses in Research

• Experimental Control: C1.18.4 is nearly always used as an isotype-matched negative control in experiments involving mouse primary antibodies of the IgG2a subclass, especially in flow cytometry, immunostaining, and ELISA assays.
• Assessment of Specificity: The clone allows researchers to distinguish true positive signals from background noise by estimating the degree of non-specific binding, ensuring that experimental results are attributable to specific antigen–antibody interactions rather than Fc receptor or other nonspecific interactions.
• Cross-reactivity Testing: C1.18.4 has been screened on a variety of resting and activated cells, as well as live and fixed mouse, rat, and human tissues, confirming minimal cross-reactivity and validating its suitability as a robust negative control.
• In Vivo Applications: While commonly used in vitro, C1.18.4 is also described for in vivo studies, particularly where a matched isotype control is required for mouse experiments.

No Intrinsic Biological Findings
Importantly, scientific literature does not attribute unique biological effects to clone C1.18.4 itself—its value in research is procedural, not mechanistic. When cited, the focus is on its function as a comparator, not on active biological roles.

Technical Specifications

• Storage: For short-term use, store at 2–8°C; for long-term, at –20°C or lower.
• Commercial Availability: Widely available from multiple vendors in various formulations for diverse laboratory applications.

Summary Table: Utility and Application

Key Studies Citing C1.18.4

• Blood (Ikeda et al., 2003): Used as a negative control in mouse hematopoietic experiments.
• Journal of Immunology (Wright et al., 2000): Employed to validate specificity in immune cell analysis.
• Journal of Investigative Dermatology (Nishikawa et al., 2000): Used for isotype control in skin immunology.

Notable Functional Study (Contextual Example)

A study showed that sialylated mouse IgG2a antibodies (using C1.18.4 as an irrelevant control) did not suppress anti-TNP antibody-mediated responses, reinforcing its role as a negative control rather than a functional modulator.

Conclusion

The key scientific finding regarding clone C1.18.4 is its universal acceptance as a high-quality, minimal cross-reacting, isotype-matched negative control in mouse biomedical research. It is cited frequently not for discovery of biological mechanisms, but for ensuring rigor and validity in antibody-based assays. No direct citations relate to novel biological functions or therapeutic properties of the clone itself.

Dosing regimens of clone C1.18.4 in mouse models are not standardized and typically vary depending on the design of the experimental study, as its main function is as an IgG2a isotype control to match the dose, route, and schedule of the test antibody in each specific model.

Researchers generally follow these principles in dosing:

• Dosage: The dose of C1.18.4 is usually chosen to match the concentration of the experimental antibody, often ranging from microgram to milligram quantities per mouse (e.g., 5 mg/kg, 100 μg/dose), as appropriate to the control requirements of that particular study. There is no universal dose for C1.18.4 because its purpose is purely as a non-reactive comparator; dosing depends on the volume and concentration used for the experimental therapies being tested in the same mouse model.
• Route: Administration is typically by intraperitoneal injection (IP), but investigators may use other routes (e.g., intravenous, subcutaneous) that align with the primary antibody administration scheme.
• Frequency/Schedule: The dosing frequency matches the test antibody regimen, commonly ranging from single-dose to multiple doses per week (e.g., 2×/week for several weeks).
• Mouse Model Variation: There is no evidence that dosing of C1.18.4 is independently adjusted according to mouse strain, disease model, or age; instead, dosing is matched to the specific experimental or therapeutic antibody and protocol being used.

Key points:

• Clone C1.18.4 is almost exclusively used as a control, so its dosage is dictated by the experimental design rather than its biological effect.
• No dose optimization studies for C1.18.4 exist for different mouse models due to its role as a negative control.
• For detailed regimens, individual published studies should be consulted; these will report the exact dose, route, and schedule as applied in the specific context, always corresponding to the primary antibody being tested.

In summary, C1.18.4 dosing regimens are variable and matched directly to the experimental antibody protocol rather than to mouse model type or characteristics.