When a mast cell armed with IgE antibodies previously produced in response to an antigen is exposed to the same antigen, the cell is activated, leading to the release of an arsenal of powerful mediators that are responsible for immediate hypersensitivity reactions. Which of the following processes triggers the release of these vasoactive substances?
A 38-year-old man with a history of severe allergies experiences anaphylaxis shortly after eating a meal containing peanuts. The patient’s condition rapidly deteriorates, with symptoms including hives, difficulty breathing, and a drop in blood pressure. His anaphylactic reaction is determined to be mediated by antigen-specific IgE antibodies bound to high-affinity receptors on the surface of […]
Which of the following is most likely to be elevated in the serum due to an anaphylactic reaction?
A 40-year-old man with a history of relapsing-remitting multiple sclerosis (MS) presents to his neurologist with increasing disability, including weakness, spasticity, and visual disturbances. Despite previous treatments, his condition has continued to worsen. The neurologist recommends treatment with rituximab infusion, a novel therapeutic approach that specifically targets a subset of immune cells implicated in the […]
A 52-year-old woman with metastatic lung cancer is undergoing immunotherapy as part of her treatment regimen. The therapy involves a monoclonal antibody that targets a specific cell surface receptor found on T lymphocytes. By blocking this receptor, the therapy enhances the ability of T cells to recognize and eliminate cancer cells. Which of the following […]
A 7-year-old boy is referred to a pediatric immunology clinic due to a history of recurrent bacterial and fungal infections. His medical history reveals that he has had multiple skin abscesses, pneumonia, and lymphadenitis episodes over the past few years. During a physical examination, the physician notices numerous granulomatous skin lesions. Laboratory testing shows that […]
Which immune effector cell type has a strong cytolytic function to identify and kill tumor cells directly without antigen presentation?
A 25-year-old woman develops severe allergic rhinitis upon entering a house with a cat. She experiences sneezing, nasal congestion, and watery eyes within minutes. Her symptoms persist for hours after leaving the house. Which of the following statements best describes the underlying immunologic mechanism of her symptoms?
Which of the following substances is most likely directly responsible for allergic rhinitis?
Impairment of which of the following mechanisms is a great risk factor for infections by encapsulated microorganisms?