Immunolabeling is a laboratory technique used to identify antigens of interest in a tissue sample. This can be useful for diagnostics as well as research, where immunolabeling can play an important role in clinical trials, epidemiology studies, and evaluation of specific disorders. Properly labeled samples can be examined under a microscope to collect and record information that may be relevant to a scientist’s work or a medical diagnosis. Some researchers perform their own immunolabeling, while others may delegate it to laboratory technicians or contract it to a service.
The first step in the immunolabeling process is the preparation of the sample to address concerns about potential contaminants and other issues. It is fixed appropriately in a medium suitable for the type of material under evaluation so a technician can proceed to the next step, adding an antibody that will bind to the antigen of interest. This requires knowing which antigen is the target and selecting an appropriately reactive antibody; scientific suppliers sell immunolabeling kits with commonly used antibodies and it’s also possible to order custom products for particular projects.
Technicians follow this step with the addition of a second antibody bound to a tag. The nature of the tag can vary; it may be designed to fluoresce under certain light, or it could be made from a material that will be picked up on a scanning electron microscope, for example. These bind to the antibodies present in the sample and will highlight them when the technician views the sample under a microscope. Using cameras specifically designed for use in microscopy, the technician can take photographs to record the findings.
This laboratory method follows a very precise protocol set by the facility to ensure consistency and reliability in results. Technicians and researchers follow a lab manual that dictates the types of fixatives and washes to use, and how to prepare samples. This means that if a test is repeated, the results should be same, as variables like a different fixative wouldn’t influence the results; this can be important for validity in scientific research. When immunolabeling is used in research, the process is discussed in detail in scientific publications to make it possible for other researchers to independently verify the findings.
As a tool for research, immunolabeling can help scientists do things like track the movement of drugs through tissue, understand how infectious disease attack specific organs, and monitor immune responses to allergens. This allows them to develop new approaches to the treatment and management of disease, in addition to providing more general information that may be useful in ongoing research. For those who are interested, images of immunolabeling are available through scientific publications; fluorescent labels can reveal particularly striking and interesting patterns on lab samples.