In Module 3.4, we learned about several antibody-based experimental techniques frequently used in research and clinical labs around the world. Among these techniques, I found Western Blots and Enzyme Linked Immunosorbent Assay (ELISA) to be the most interesting.
Western blotting allows researchers to separate and quantify a specific protein in a sample. An article by Tahrin Mahmood and Ping-Chang Yang explains the technique and the theory of Western blots. Proteins are separated by means of electrophoresis. Next, the proteins are transferred to a nitrocellulose blotting paper. The nitrocellulose paper is then blocked with a basic protein – milk proteins, for example. Following that, a primary antibody is added to the solution, where it can bind to the protein it is specific for. A secondary antibody is added, which binds to the Fc region of the primary antibody. Finally, the antibody’s location is found by mixing the blotting paper with a substrate, which reacts to an enzyme on the secondary antibody. The substrate changes color when it interacts with the antibody. (1)
ELISA is a technique that allows scientists to diagnose diseases by detecting/quantifying antibodies and antigens. Sino Biological Inc summarizes the ELISA procedure. ELISAs are carried out in 96-well plates, which are coated with samples of antibody proteins. All the wells are then “blocked,” preventing results that are false positives. After that, all the wells are given primary antibody, which will bind to its specific antigen if it’s present. Conjugated secondary antibody specific for the primary antibody is added to remove any excess antibody. Just like Western Blots, a substrate reacts with the conjugated secondary antibody and a colored product will appear. (2)
These research techniques are being used for early diagnosis and treatment of patients, which I find quite impressive. The fact that a single, specific antigen can be rapidly targeted and treated is fascinating. In animals, veterinary titer tests are used to check blood antibody levels. This helps vets decide if the animal needs a booster vaccination for diseases like parvo, rabies, or distemper. Instead of administering yearly doses, vets can check to see if the vaccination can be skipped for that year or longer. Question: can these techniques be used to monitor how well an infant’s immune system reacts to a vaccination? If their immune systems get built up from a single vaccination, would sequential boosters really be necessary?