24.E: Diseases of the Immune System (Exercises)
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- Ying Liu
- City College of San Francisco
19.1: Hypersensitivities
An allergy is an adaptive immune response, sometimes life-threatening, to an allergen. Hypersensitivity reactions are classified by their immune mechanism.
Multiple Choice
Which of the following is the type of cell largely responsible for type I hypersensitivity responses?
- erythrocyte
- mast cell
- T lymphocyte
- antibody
- Answer
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B
Type I hypersensitivities require which of the following initial priming events to occur?
- sensitization
- secondary immune response
- cellular trauma
- degranulation
- Answer
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A
Which of the following are the main mediators/initiators of type II hypersensitivity reactions?
- antibodies
- mast cells
- erythrocytes
- histamines
- Answer
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A
Inflammatory molecules are released by mast cells in type I hypersensitivities; type II hypersensitivities, however, are characterized by which of the following?
- cell lysis (cytotoxicity)
- strong antibody reactions against antigens
- leukotriene release upon stimulation
- localized tissue reactions, such as hives
- Answer
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A
An immune complex is an aggregate of which of the following?
- antibody molecules
- antigen molecules
- antibody and antigen molecules
- histamine molecules
- Answer
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C
Which of the following is a common treatment for type III hypersensitivity reactions?
- anti-inflammatory steroid treatments
- antihistamine treatments
- hyposensitization injections of allergens
- RhoGAM injections
- Answer
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A
Which of the following induces a type III hypersensitivity?
- release of inflammatory molecules from mast cells
- accumulation of immune complexes in tissues and small blood vessels
- destruction of cells bound by antigens
- destruction of cells bound by antibodies
- Answer
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B
Which one of the following is not an example of a type IV hypersensitivity?
- latex allergy
- Contact dermatitis (e.g., contact with poison ivy)
- a positive tuberculin skin test
- hemolytic disease of the newborn
- Answer
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D
Fill in the Blank
Antibodies involved in type I hypersensitivities are of the ________ class.
- Answer
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IgE
Allergy shots work by shifting antibody responses to produce ________ antibodies.
- Answer
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IgG
A person who is blood type A would have IgM hemagglutinin antibodies against type ________ red blood cells in their plasma.
- Answer
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B
The itchy and blistering rash that develops with contact to poison ivy is caused by a type ________ hypersensitivity reaction.
- Answer
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IV
Short Answer
Although both type I and type II hypersensitivities involve antibodies as immune effectors, different mechanisms are involved with these different hypersensitivities. Differentiate the two.
What types of antibodies are most common in type III hypersensitivities, and why?
Critical Thinking
Patients are frequently given instructions to avoid allergy medications for a period of time prior to allergy testing. Why would this be important?
In some areas of the world, a tuberculosis vaccine known as bacillus Calmette-Guérin (BCG) is used. It is not used in the United States. Every person who has received this vaccine and mounted a protective response will have a positive reaction in a tuberculin skin test. Why? What does this mean for the usefulness of this skin test in those countries where this vaccine is used?