Medical Immunology (328 questions with correct answers)

What is the role of the immune system in host defense? - Answer To provide defense against antigens and other infectious agents via innate immunity or adaptive immunity. What is the difference between central and peripheral tolerance? - Answer Central tolerance is the mechanism by which newly developing T cells and B cells are rendered non-reactive to self while peripheral tolerance is immunological tolerance developed after T and B cells mature and enter the periphery. Define the term tolerance and state what happens when we lose this mechanism - Answer Tolerance is the ability of the body to discriminate self from non self molecules (antigens) and destroy non-self molecules. When something goes wrong with this mechanism this leads to autoimmunity a disorder in which self molecules are interpreted as foreign and they trigger an immune response. What are the properties of antigens and which molecules are the most immunogenic? - Answer Antigens are foreign, chemically complex and they have a molecular weight greater than 6kD. Sequence of immunogenicity: Proteins > Polysaccharides > Nucleic Acids > Lipids (Proteins are the most immunogenic) Three terms that are used to refer to the component of the antigen with which receptors of the immune cells recognize and interact - Answer 1) Epitope