QS Study

Haptens are molecules of low molecular wt which itself have no antigenic activity but if combine with appropriate carrier molecule capable of producing an antibody with which it reacts specifically. e,g., penicillin, picryl chloride etc. It is a small molecule which, when combined with a larger carrier such as a protein, can elicit the production of antibodies which bind specifically to it. A hapten is fundamentally an incomplete antigen. These small molecules can bring out a resistant reaction only when attached to a huge carrier such as a protein; the carrier naturally does not obtain a resistant retort by itself.

Many drugs that reason allergic reactions, such as penicillin, act as haptens. When injected or ingested, penicillin reacts chemically with proteins in the body to form a hapten-carrier complex that can lead to the life-threatening syndrome called anaphylaxis. Other haptens contain synthetic substances, such as the organic compounds benzene resonate or trinitrophenol, and naturally occurring polysaccharides, such as lactose.