Jayne was an eighteen year old freshman in college. On her second day at the college, she and her new roommate went to a "meet and greet" get together in their

dorm. There were a lot of snacks and drinks there. After eating a cookie Jayne started developing nausea, itchy skin with large welts, a tingling sensation and tightness in her throat, dizziness and difficulty breathing, and a feeling of doom. She tried to speak to her roommate but her voice was very hoarse. She became unconscious and was rushed to the ER. When the medical personnel examined her she was hypotensive, with tachycardia; her skin was clammy. When the nurse looked in her purse she saw and Epipen injector. On questioning the RA from the residence hall, the ER staff found out that the cookies had peanuts in them. On administering epinephrine, Jayne quickly regained consciousness, her blood pressure rebounded to normal, and the heart rate slowed down. She was discharged the next day. Prompts: 1) What is your diagnosis about Jayne's condition? 2) What is an "antigen-presenting cell" and what role does this type of cell play in an immune response? 3) Explain the interaction that occurs between a T-helper lymphocyte and a B cell when the B cell is being induced to produce peanut-specific IgE. In your explanation, explain the role that the peanut allergen plays in this interaction. 4) In immediate hypersensitivity, the initial exposure to an allergen usually does not produce any symptoms. The symptoms, such as those involved in anaphylaxis, usually appear in the second exposure. What events are occurring during this initial exposure that sensitizes a person to an allergen? In your description include the role of B cells, T cells, IgE, mast cells, basophils and the allergen. 5) Describe how IgE binds and reacts with basophils and mast cells.