This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
[{'content': 'Which of the following statements is true about hapten- \nSelect and explain. \nA. It induces brisk immune response, B. It needs carrier to induce immune response, C. It is a T-independent Antigen, D. It has no association with MHC', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 1. Haptens are small organic molecules that are antigenic but not immunogenic.They are not immunogenic because they cannot activate helper T cells. Failure of hapten to activate helper T cells is due to their inability to bind to MHC proteins; they cannot bind because they are not proteins and only proteins can be presented by MHC proteins. Moreover, haptens are univalent hence cannot activate B cells by themselves. 2. In general, only large molecules, infectious agents, or insoluble foreign matter can elicit an immune response in the body.', 'role': 'assistant'}]