How to Choose An Isotype Control Antibody

What are Isotype Control Antibodies?

Isotype controls are antibodies that closely resemble primary antibodies used in experiments but lack specificity for the target protein of interest. They have the same immunoglobulin class and subclass as the primary antibody, ensuring compatibility with the experimental setup. Isotype controls are particularly useful in techniques such as flow cytometry, immunohistochemistry, and immunofluorescence, where they help determine the extent of non-specific binding and background staining.

What Causes Non-Specific Background Staining?

Background signals in immunological experiments can arise from various sources. One common cause is the non-specific binding of the primary antibody to Fc receptors expressed on cells, such as macrophages, B cells, monocytes, and dendritic cells, leading to unintended binding and background staining.

In addition to interacting with Fc receptors, the primary antibody can also bind non-specific to lipids, carbohydrates, and off-target proteins or debris present in the sample, resulting in undesired background signals.

Why are Isotype Control Antibodies Important?

The use of appropriate isotype control antibodies can ensure the generation of reliable and accurate data in many applications, including:

In vitro: Flow cytometry, fluorescence immunocytochemistry, immunohistochemistry, ELISA, Western blotting, Luminex® multiple assays and other assays

In vivo: preclinical animal studies requiring functional antibodies

How to Choose the Best Isotype Control Antibody?

Same Species and Ig Class
One crucial consideration when choosing an isotype control is to match the host species and class of the primary antibody. The host species refers to the organism from which the antibody is derived, such as a mouse, rabbit, or goat. It is essential to select an isotype control derived from the same host species to ensure compatibility and minimize cross-reactivity.
Additionally, the class of the isotype control antibody should match that of the primary antibody. Immunoglobulins, or antibodies, are classified into different classes, including IgG, IgM, IgA, IgE, and IgD. Each class has distinct functions and locations within the immune system. Matching the class of the isotype control with the primary antibody is particularly important in flow cytometry and double-labeling experiments, as it helps avoid potential interference and misleading results.

Same Ig Subclass
The Ig subclass refers to variations within a class, such as IgG1, IgG2a, IgG2b, etc. Different subclasses may have different affinities for Fc receptors and distinct binding properties. Therefore, it is recommended to choose an isotype control with the same Ig subclass as the primary antibody to ensure compatibility and accurate interpretation of results.

Same Label a Primary Antibody
Considering labeling compatibility between the isotype control and the detection method is essential for accurate results. If the primary antibody or secondary detection reagent is conjugated with a specific label, such as biotin or a fluorophore, the isotype control should also be conjugated with the same label. This ensures that both the experimental antibody and the isotype control behave similarly during the staining process.

Other Factors to Consider
To ensure similarity between your primary antibody and the isotype control, several factors should be considered. First, it is recommended to obtain both antibodies from the same supplier. This enhances compatibility and ensures consistency in the manufacturing process. Second, the clonality should be considered. Regardless of whether the primary antibody is polyclonal or monoclonal, selecting an isotype control with the same clonality helps maintain similarity and compatibility between the two antibodies. Beyond this, try to select an isotype control that matches the format, purity, storage, and handling conditions of the primary antibody. This ensures consistency in experimental conditions and minimizes variation.

Why Choose Our Isotype Control Antibodies?

Exceptional purity

Ultra-low endotoxin levels

Pathogen free

Low protein aggregation

At Creative Diagnostics, we offer a wide range of validated isotype control antibodies suitable for various applications. Our products undergo rigorous quality control procedures to ensure their performance and reliability. Visit our website to explore our comprehensive selection of isotype control antibodies and find the perfect match for your research needs.

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