Which of the following statements best describes a hapten?: (A) Haptens activate T cells, (B) Penicillin is a hapten, (C) Haptens do not react with specific antibody, (D) Haptens bind the major histocompatibility complex
Answer is B. Haptens react with antibodies but they are not immunogenic. They do not activate T cells and cannot bind the major histocompatibility complex. Penicillin is a hapten and can cause severe life threatening allergic reaction.