Concept explainers
Introduction:
Hypersensitivity is an immune response against a foreign substance (antigen) that is exaggerated beyond the norm such as the smell of perfume, dust, pollen causes wheezing, running nose or watery eyes. These symptoms indicate that the person is suffering from a hypersensitive response.
Answer to Problem 1MC
Correct answer:
The immunoglobulin class that mediates type I hypersensitivity is IgE. Therefore, option (e) is correct.
Option (e) is given as “IgE”.
Explanation of Solution
Justify reason for the correct statement:
Immunoglobulin E combines with the mast cells and produces degranulation that results in inflammation. Histamines, protease, kinens, leukotrienes, and prostaglandins are mediators of inflammation that triggers the type I hypertensive reaction. Hence, option (e) is correct.
Justify reasons for the incorrect statements:
Option (a) is given as “IgA”.
IgA is “secretory immunoglobulin” that is found in mucous secretions and play role in mucosal immunity, not hypersensitivity. Hence, it is a wrong answer.
Option (b) is given as “IgM”.
IgM is the first antibody that appears during the primary immune response and do not mediate hypersensitivity reaction. Hence, it is a wrong answer.
Option (c) is given as “IgG”
It is the only immunoglobulin that crosses the human placenta and provides humoral immunity. Hence, it is a wrong answer.
Option (d) is given as “IgD”
This immunoglobulin binds to mast cells and basophils and activates them to secrete “antimicrobial factors”. These factors play role in the respiratory immune defense. Hence, it is a wrong answer.
Hence, options (a), (b), (c), and (d) are incorrect.
IgE mediates the type I hypersensitivity.
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Chapter 18 Solutions
Modified Mastering Microbiology with Pearson eText -- Standalone Access Card -- for Microbiology with Diseases by Taxonomy (5th Edition)