Question

What are haptens?

Answer 1

Hint: Hapten is an incomplete antigen that is known to induce an immunological response when attached to a carrier. It plays an important role in vaccine development.

Complete Answer:
- Haptens were first discovered by Landsteiner while studying how antigen-antibody binding worked, and in more recent times has been used in the search for vaccines against infectious diseases.
- A pattern is used to construct a synthetical vaccine. A hapten is a small molecule that alone can not induce an immunogenic response until it binds to a carrier.
- Hapten binds to a carrier molecule with a covalent bond. The carrier molecule is mostly protein. This hapten-carrier complex results in the production of antibodies, hence the immunogenic response is initiated by B-cells of lymphocytes.
- An antibody cannot elicit an immune response on its own even if it binds to antibodies. An example of hapten is urushiol toxin that is found in poison ivy. Some of the heptanes are known to induce an autoimmune response, e.g., hydralazine.
- Fluorescein detects proteins therefore they are used in molecular biology. In drugs, such as penicillin causes an allergic response. Hapten examples are trinitrophenol and also naturally occurring polysaccharides lactose.

Additional information:
- Similarities between hapten and antigens are they are antigenic and are present on the exterior part of microbes,pathogens or foreign bodies.
- Both forms a part of the defense mechanism system and ability to bind to antibodies via weak interactions such as ionic interaction, hydrogen bonding interactions and hydrophobic interaction.

Note:
- The immunogen is a stimulus that is capable of producing an immune response.
- Antigens are the molecule that binds specifically to immune response components, lymphocytes (antibodies ), or their receptor (T-cell receptor). Not all the antigens are immunogen, but all immunogens are antigens.
- Antigen and immunogen, both elicit an immune response but a hapten is incapable of inducing an immune response unless they bind to some carrier molecules.