An enzyme-labeled antibody technique is a test for identifying the presence of a targeted antigen within an infectious organism or diseased cell. The enzymes in the antibody serve as the label and are referred to as reporters. An enzyme can be chosen for its targeted delivery, specificity, and rapid reaction kinetics. Enzyme labels are also capable of catalyzing reactions, which do not require light sources, making them easier to use than fluorescent labels.
The enzyme-labeled antibody technique (ELAT), also known as the enzyme-linked immunosorbent assay (ELISA), is a test for identifying the presence of a targeted antigen within an infectious organism or diseased cell. The enzyme in the antibody serves as the label, and it's typically linked to gold particles via a chemical reaction.
An enzyme-labeled antibody technique is a test for identifying the presence of a targeted antigen within an infectious organism or diseased cell.
The test works by first coating the suspected organism with an enzyme, then attaching an antibody that reacts to that enzyme. If antibodies are present in the organism, they will react and form a visible "dot" of color on the organism's surface.
Enzymes are the reporters in enzyme-labeled antibodies. The enzymes in a labeled antibody serve to detect the presence of an antigen by catalyzing a chemical reaction that produces a colored product or light. The enzyme reporter is attached to the antibody, which is used to specifically bind it to its target antigen (the substance being tested). Because these interactions occur across a membrane, they can be detected using many different methods including colorimetry, fluorescence and chemiluminescence.
If you are looking for fast and accurate results, enzyme-labeled antibody techniques are a great choice. These methods use an enzyme that is attached to a specific protein or antibody, which can be used to detect the original molecule. The enzyme is then added to a sample containing the target molecule. Once the target molecule is detected, it will be marked by the enzyme and visualized for analysis by scientists.
Enzymes are natural catalysts that make chemical reactions happen faster. In an enzyme-labeled antibody technique, the enzyme is attached to the antibody and catalyzes a reaction when it binds to a target antigen. This technique can be used in many ways: enzymes can be chosen for their targeted delivery, specificity, and rapid reaction kinetics. The choice of the enzyme depends on what type of product you are trying to make and what kind of assay you want to do with your samples (i.e., Western blotting).
Enzyme labels are also capable of catalyzing reactions, which do not require light sources, making them easier to use than fluorescent labels. Enzyme labeled antibodies have been used for the detection of a number of different chemicals including: proteins, DNA and RNA.
There are several different types of enzyme-labeled antibody techniques, but they all fall under the umbrella of immunofluorescence. In a direct fluorescence assay (DFA), an unlabeled primary antibody is incubated with cells that have been stained with a fluorescein-conjugated secondary antibody. The primary antibody will bind specifically to the target antigen on cell surfaces, which triggers the fluorescent label to bind as well. The result is a bright green spot or blotch of fluorescence in cells containing bound primary antibodies and that have been treated with the stain (Figure 1).
In an indirect fluorescence assay (IFA), a primary antibody is used to detect multiple antigens at once. This is ideal for instances where a primary antibody is not available or when you simply want to increase your detection sensitivity. As with the enzyme-labeled antibody technique, IFA can also be used in conjunction with this method.
A DFA directly labels antibodies specific to an antigen with a fluorophore. Unlike a DFA, an IFA involves incubating cells with unlabeled primary antibodies that bind specifically to the target antigen followed by fluorescently labeled secondary antibodies that bind to the primary antibodies. The secondary antibodies are either polyclonal or monoclonal. This method allows researchers to use multiple primary antibodies at once by using different fluorophores on the secondary antibodies.
For example, one of your colleagues might want to know if there are any proteins in his sample that contain both myoglobin and hemoglobin. He could do this using an indirect immunofluorescent assay (IFA). He would start off by adding a mixture of fluorescently-labeled Type 1, 2A and 2C myoglobins into wells containing his test cells (these fluorescences will be somewhat similar). Then he would add Type 1B myoglobins into some of these wells and type 2A/2C hemoglobins into others; this way he can clearly see differences in these fluorescences under UV light (the color is not as important here).
To summarize, enzyme-labeled antibody techniques are a useful method for identifying the presence of different antigens within a cell or organism. They are used in both research and clinical settings. A DFA directly labels antibodies specific to an antigen with fluorophore, whereas an IFA involves incubating cells with unlabeled primary antibodies that bind specifically to the target antigen followed by fluorescently labeled secondary antibodies that bind to the primary antibodies. The secondary antibodies are either polyclonal or monoclonal; this method allows researchers to use multiple primary antibodies at once by using different fluorophores on the secondary antibodies