Enzyme-Linked Immunosorbent Assay (ELISA) - Multi-Lingual Captions

Summary

This animation explains the process of an enzyme-linked immunosorbent assay (ELISA), a commonly used serologic test. The test is performed in multi-well microtiter plates where patient serum dilutions are added to antigen-coated wells. Antibodies bind to the antigen, and a second antibody conjugated to an enzyme is used to generate a color reaction when a substrate is added. This color development indicates the presence of specific antibodies, with the intensity of the color reflecting the antibody concentration. The titer is determined by the highest dilution showing definite color development.

Takeaways

• 😀 ELISA (Enzyme-Linked Immunosorbent Assay) is a widely used test for detecting antibodies in serum.
• 😀 The test is commonly performed using multi-well microtiter plates, which allow for easy preparation and testing of serum dilutions.
• 😀 The assay works by coating the wells with the antigen of interest, which can be commercially prepared by the manufacturer.
• 😀 Patient serum is added to the wells, and if antibodies against the antigen are present, they will bind to the antigen fixed on the well's surface.
• 😀 Only antibodies specific to the antigen will bind, ensuring accurate detection.
• 😀 After adding the serum, the wells are washed to remove any unbound antibodies.
• 😀 An animal antibody against human antibodies is then introduced, and it is covalently linked to an enzyme.
• 😀 The wells are washed again to remove unbound enzyme-conjugated antibodies.
• 😀 A color-generating enzyme substrate is added to the wells, and the enzyme on the second antibody interacts with the substrate to produce visible color.
• 😀 The intensity of the color correlates with the presence of antibodies, and the highest dilution showing distinct color is considered the titer.
• 😀 The test results can be visually observed or quantified with an electronic plate reader for precise measurements.

Q & A

What is the main purpose of the enzyme-linked immunosorbent assay (ELISA)?

The main purpose of the ELISA is to detect and measure the presence of specific antibodies or antigens in a sample, often used in serologic testing.

Why are multi-well microtiter plates used in ELISA testing?

Multi-well microtiter plates are used because they allow for easy preparation and testing of multiple serum dilutions simultaneously.

How are the wells of the plate prepared before starting the ELISA test?

The wells of the plate are coated with the antigen of interest, which is typically done by the manufacturer of the assay for commercial tests.

What happens after the patient's serum is added to the wells in the ELISA?

After the patient's serum is added, any antibodies present that are specific to the antigen will bind to it, while other non-specific antibodies will not.

Why are the wells washed after adding the patient's serum?

The wells are washed to remove any unbound antibodies, ensuring that only antigen-specific antibodies remain in the well.

What role does the second antibody play in the ELISA?

The second antibody, which is conjugated to an enzyme, binds to the human antibodies that are already bound to the antigen, helping to detect the presence of the target antibody.

Why is an enzyme-conjugated antibody used in ELISA?

The enzyme-conjugated antibody is used to generate a visible color change when it interacts with the substrate, indicating the presence of specific antibodies in the sample.

What is the purpose of the color change in the ELISA?

The color change indicates the presence of antigen-specific antibodies. The intensity of the color correlates with the amount of antibody in the sample.

How is the color intensity measured in the ELISA?

The color intensity can either be observed with the naked eye or measured using an electronic plate reader, which quantifies the color change.

What does the titer represent in the ELISA test?

The titer represents the highest dilution of serum at which a definite color change is observed, indicating the concentration of specific antibodies in the sample.