What Are Conjugated Antibodies?

Maggie J. Hall
Maggie J. Hall
Conjugated antibodies can be used to test blood samples.
Conjugated antibodies can be used to test blood samples.

Conjugated antibodies are laboratory-manufactured compounds made up of antibodies combined with dyes, chemicals, or proteins. These antibody combinations are used for research, testing, and medical treatment. Companies that manufacture these antibodies commonly classify the conjugations using labeling, loading, or tagging, which identifies the substance attached to the antibody.

Laboratories frequently create conjugated antibodies using fluorescent dyes. Antibodies labeled with luminescent molecules absorb light, but emit colors of one wavelength. These colors become visible under electron and fluorescent microscopes. Researchers use this method of antibody labeling for cell and tissue staining, cell sorting, and blot immunoassays.

When testing for an infection or particular disease process, for example, technicians obtain a patient’s blood and mix diluted samples with the dye. They then incubate these conjugated antibodies with infected and uninfected cells. If a patient has antibodies toward the specific microbe antigen, the antibody and antigen merge. These connections, because of the dye, become visible under a fluorescent microscope, and the patient tests positive for that particular ailment. Lab specialists commonly use this extensive testing process for detecting human immunodeficiency virus (HIV), Lyme disease, and certain types of encephalitis.

Histologists also use radioactive markers to track cancer or other diseases throughout the body. Conjugated antibodies tagged with radioactive particles act as homing devices, allowing physicians to determine tumor location and possible cancer metastasis. These tagged antibodies generally circulate through the body until making contact with tumors. Cameras designed to track these particles illuminate affected areas.

Using special chemical linkers, researchers load antibodies with cytotoxic medications for targeted therapy. Circulating conjugated antibodies locate abnormal tissues, triggering the release of the chemotherapeutic medication. While targeting affected tissue, this type of therapy minimizes damage to healthy surrounding tissues. Oncologists sometimes use this treatment method for non-Hodgkin’s lymphoma when other therapies fail.

An company that produces conjugated antibodies typically uses monoclonal or polyclonal antibodies to produce them. Monoclonal antibodies are cloned from a singular cell line. Researchers combine animal cells with the desired antigen, which then produces a specific antibody. Polyclonal antibody production involves injecting an animal with a particular antigen. After a period of time, the animal produces antibodies in response, which laboratory technicians retrieve through blood samples.

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    • Conjugated antibodies can be used to test blood samples.
      By: Alexander Gospodinov
      Conjugated antibodies can be used to test blood samples.