Immunolabeling

Overview

Diagram of the immunolabeling process

Immunolabeling is a technique used in molecular biology and biochemistry to detect specific proteins or antigens in a sample using antibodies. This method is widely used in research and diagnostics to study the presence and distribution of proteins in cells and tissues.

Principles of Immunolabeling

Immunolabeling relies on the specific binding of an antibody to its corresponding antigen. The antibody is typically conjugated to a detectable marker, such as a fluorescent dye or an enzyme, which allows for visualization of the antigen-antibody complex.

Types of Immunolabeling

There are several types of immunolabeling techniques, including:

• Immunohistochemistry (IHC): Used to detect antigens in tissue sections.
• Immunocytochemistry (ICC): Used for detecting antigens in cell cultures.
• Western blotting: Used to detect proteins in a gel.

Procedure

The immunolabeling process generally involves the following steps:

1. Sample Preparation: The sample, such as a tissue section or cell culture, is prepared and fixed to preserve the structure and antigenicity.
2. Blocking: Non-specific binding sites are blocked to prevent background staining.
3. Primary Antibody Incubation: The sample is incubated with a primary antibody specific to the target antigen.
4. Secondary Antibody Incubation: A secondary antibody, conjugated to a detectable marker, is applied. This antibody binds to the primary antibody.
5. Detection: The marker on the secondary antibody is visualized using appropriate methods, such as fluorescence microscopy or colorimetric detection.

Applications

Immunolabeling is used in various fields, including:

• Pathology: To diagnose diseases by detecting abnormal protein expression.
• Neuroscience: To study the distribution of neurotransmitters and receptors.
• Cancer research: To identify tumor markers and study cancer progression.

Advantages and Limitations

Immunolabeling offers high specificity and sensitivity, allowing for the detection of low-abundance proteins. However, it requires well-characterized antibodies and can be limited by cross-reactivity and non-specific binding.

Related pages

• Antibody
• Antigen
• Fluorescence microscopy
• Enzyme-linked immunosorbent assay