$$\text{RNA} \rightarrow \text{DNA}$$

$$\text{Increased capillary permeability} \rightarrow \text{Decreased blood pressure}$$

$$\text{Allergen} + \text{Sensitized mast cell} \rightarrow \text{Cross-linked IgE} \rightarrow \text{Histamine release}$$

Question 1

Which antibody is primarily responsible for mediating Type I hypersensitivity reactions, such as allergies?

Accepted Answer

IgE

Question 2

During an anaphylactic shock, which physiological change is most likely to cause a rapid drop in blood pressure?

Accepted Answer

Systemic vasodilation

Question 3

A patient receives a blood transfusion with mismatched donor erythrocytes. Which hypersensitivity type is most likely involved?

Accepted Answer

Type II

Question 4

Which immune cells are primarily responsible for mediating delayed-type hypersensitivity (Type IV)?

Accepted Answer

T cells

Question 5

What is the main mechanism by which HIV-1 leads to AIDS?

Accepted Answer

Destruction of Th cells

Question 6

Which of the following best describes the process shown in the image for the first exposure to an allergen?

Accepted Answer

Plasma cells produce IgE antibodies that bind to mast cells, sensitizing them.

Question 7

Which treatment blocks both leukotrienes and prostaglandins, and is commonly used for asthma?

Accepted Answer

Corticosteroids

Question 8

A patient develops a rash after touching poison ivy. Which hypersensitivity type is most likely responsible?

Accepted Answer

Type IV

Question 9

Which equation best represents the process by which HIV-1 reproduces in host cells?

Accepted Answer

$$	ext{RNA} ightarrow 	ext{DNA}$$

Question 10

Which of the following is a primary immunodeficiency disorder characterized by failure of lymphoid cell lines in the bone marrow?

Accepted Answer

SCID (Severe Combined Immunodeficiency)

Question 11

Which of the following is a plausible reason why the first allergic reaction is usually mild?

Accepted Answer

Mast cells and basophils are not yet sensitized by IgE antibodies.

Question 12

Which scenario best illustrates molecular mimicry leading to autoimmunity?

Accepted Answer

Foreign antigens mimic self antigens, causing the immune system to attack self tissues.

Question 13

Which hypersensitivity type involves immune complexes that are difficult for macrophages to clear, leading to inflammation in capillary beds?

Accepted Answer

Type III

Question 14

A patient with AIDS is at increased risk for which of the following conditions?

Accepted Answer

Kaposi sarcoma

Question 15

Which of the following best describes the effect of antihistamines in allergy treatment?

Accepted Answer

They block the action of histamine, reducing allergy symptoms but causing drowsiness.

Question 16

Which equation best represents the relationship between capillary permeability and blood pressure during anaphylactic shock?

Accepted Answer

$$	ext{Increased capillary permeability} ightarrow 	ext{Decreased blood pressure}$$

Question 17

Which of the following is a secondary immunodeficiency disorder most commonly caused by a retrovirus?

Accepted Answer

AIDS

Question 18

Which of the following best explains why allergen immunotherapy (allergy shots) may not always be effective?

Accepted Answer

The immune system may not develop tolerance or diminish the IgE response.

Question 19

Which of the following is a plausible consequence of a genetic primary immunodeficiency disorder affecting complement proteins?

Accepted Answer

Increased risk of bacterial and parasitic infections

Question 20

Which equation best represents the cascade of events leading to an allergic reaction upon subsequent exposure to an allergen, as shown in the image?

Accepted Answer

$$	ext{Allergen} + 	ext{Sensitized mast cell} ightarrow 	ext{Cross-linked IgE} ightarrow 	ext{Histamine release}$$

Immune Disorders: Hypersensitivity, Immunodeficiency, and Autoimmunity

Study Guide - Practice Questions