Q: Which equation describes the formation of antigen-antibody complexes in Type III hypersensitivity reactions?

$$Ag + Ab \rightarrow AgAb \text{ complex}$$

Q: Which equation best represents clonal deletion during fetal development to ensure self-tolerance?

$$\text{Self-reactive T/B cells} \xrightarrow{\text{deletion}} \text{No self-reactive cells}$$

Question 1

Which type of hypersensitivity reaction is characterized by the crosslinking of IgE antibodies on mast cells or basophils, leading to rapid degranulation and release of histamine and leukotrienes?

Accepted Answer

Type I (Immediate, IgE-mediated)

Question 2

A patient receives a blood transfusion and develops hemolysis due to antibodies binding to cell-surface antigens. Which hypersensitivity type is involved, and what immunoglobulin is most likely responsible?

Accepted Answer

Type II; IgG

Question 3

Which equation best represents the complement activation cascade leading to opsonization, inflammation, and cytolysis?

Accepted Answer

$$C1 \rightarrow C2 + C4 \rightarrow C3 \rightarrow C3a + C3b$$

Question 4

Which process enhances phagocytosis by coating microbes with C3b, as shown in the provided image?

Accepted Answer

Opsonization

Question 5

A newborn develops hemolytic disease due to maternal anti-Rh antibodies attacking fetal red blood cells. Which immunological principle explains why this reaction occurs only after the mother is sensitized?

Accepted Answer

Memory cells produce a rapid and robust response upon re-exposure

Question 6

Which of the following is a delayed hypersensitivity reaction mediated by T cells, often seen in response to poison ivy exposure?

Accepted Answer

Type IV (Delayed, T cell–mediated)

Question 7

During a skin test for allergies, what immunological mechanism is being evaluated?

Accepted Answer

Type I hypersensitivity (IgE-mediated)

Question 8

Which of the following drugs suppresses IL-2 to prevent graft rejection?

Accepted Answer

Cyclosporine

Question 9

A patient develops purpura after receiving a drug that binds to platelets, forming a complex recognized by antibodies. Which hypersensitivity type is this, and what is the outcome?

Accepted Answer

Type II; complement activation leads to platelet destruction and hemorrhaging

Question 10

Which equation describes the formation of antigen-antibody complexes in Type III hypersensitivity reactions?

Accepted Answer

$$Ag + Ab ightarrow AgAb 	ext{ complex}$$

Question 11

Which type of tissue graft uses tissue from a genetically identical individual, such as a twin?

Accepted Answer

Isograft

Question 12

Why are transplants to privileged sites (such as the eye or brain) less likely to be rejected?

Accepted Answer

Inflammation in these sites would be detrimental, so immune responses are suppressed

Question 13

Which method is used to serologically type HLA molecules for tissue transplantation compatibility?

Accepted Answer

Antibody binding followed by complement and trypan blue dye uptake

Question 14

Which equation best represents clonal deletion during fetal development to ensure self-tolerance?

Accepted Answer

$$	ext{Self-reactive T/B cells} \xrightarrow{	ext{deletion}} 	ext{No self-reactive cells}$$

Question 15

Which of the following is NOT a mechanism by which cancer cells evade immune detection?

Accepted Answer

Expressing new or increased levels of tumor antigens

Question 16

Which equation represents the risk increase for Graves' disease with specific HLA types, as shown in the table?

Accepted Answer

$$	ext{Risk} = 10 	ext{ to } 12 	imes 	ext{general population}$$

Question 17

Which immunodeficiency is characterized by a lack of both T and B cells, leading to severe infections?

Accepted Answer

Severe combined immunodeficiency

Question 18

Which cancer immunotherapy involves engineering T cells to express chimeric antigen receptors (CARs) targeting tumor antigens?

Accepted Answer

CAR T cell therapy

Question 19

A patient with multiple sclerosis has a 5-fold increased risk due to specific HLA types. Which equation best represents this?

Accepted Answer

$$	ext{Risk} = 5 	imes 	ext{general population}$$

Question 20

Which of the following is a real-world example of a Type IV hypersensitivity reaction?

Accepted Answer

Contact dermatitis from poison ivy

Chapter 19Disorders of the Immune System

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