Q: Which equation best represents the complement-mediated cell lysis in Type II hypersensitivity?

$$\text{Ag} + \text{Ab} \rightarrow \text{Ag-Ab complex} \rightarrow \text{Complement activation} \rightarrow \text{Cell lysis}$$

Question 1

Which type of hypersensitivity reaction is characterized by the rapid release of histamine from mast cells and basophils, and can result in systemic anaphylaxis?

Accepted Answer

Type I (anaphylactic)

Question 2

According to the hygiene hypothesis, what is the primary reason for increased hypersensitivity reactions in modern societies?

Accepted Answer

Lack of exposure to antigens lowers immune tolerance

Question 3

A patient receives a desensitizing injection for allergies. What is the immunological mechanism behind this treatment?

Accepted Answer

Production of IgG antibodies that act as blocking antibodies

Question 4

Which blood group can receive blood from all other groups according to the ABO system?

Accepted Answer

AB

Question 5

Hemolytic disease of the newborn occurs when:

Accepted Answer

Rh– mother produces anti-Rh antibodies that cross the placenta

Question 6

In Type III hypersensitivity, what is the consequence of immune complexes lodging in basement membranes?

Accepted Answer

Complement activation and inflammatory tissue damage

Question 7

Which autoimmune disease is caused by antibodies that mimic Thyroid Stimulating Hormone (TSH), leading to increased thyroid hormone production?

Accepted Answer

Graves’ disease

Question 8

What is the function of cyclosporine in transplantation immunosuppression?

Accepted Answer

Suppresses IL-2 production

Question 9

Which cells are primarily targeted and destroyed in AIDS, leading to immunodeficiency?

Accepted Answer

CD4+ T cells (TH cells)

Question 10

A patient with a CCR5 mutation is exposed to HIV but does not become infected. What is the most likely explanation?

Accepted Answer

The mutation prevents HIV from binding to the coreceptor

Question 11

Which diagnostic method is used to detect HIV antibodies in a patient’s blood?

Accepted Answer

ELISA

Question 12

Why is it difficult to develop an effective vaccine against HIV?

Accepted Answer

HIV mutates rapidly and has multiple clades

Question 13

Which equation best represents the complement-mediated cell lysis in Type II hypersensitivity?

Accepted Answer

$$	ext{Ag} + 	ext{Ab} ightarrow 	ext{Ag-Ab complex} ightarrow 	ext{Complement activation} ightarrow 	ext{Cell lysis}$$

Question 14

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

Accepted Answer

Allergic contact dermatitis from poison ivy

Question 15

What is the primary mechanism by which cytotoxic T lymphocytes (CTLs) destroy cancer cells?

Accepted Answer

Lysis of cancer cells via perforin and granzymes

Question 16

Which drug class is used in HAART to inhibit HIV reverse transcriptase?

Accepted Answer

Nucleoside reverse transcriptase inhibitors

Question 17

A patient with severe combined immunodeficiency (SCID) has defects in which cell types?

Accepted Answer

B, T, and stem cells

Question 18

Which of the following best describes the process of immune complex-mediated tissue damage in Type III hypersensitivity?

Accepted Answer

Immune complexes activate complement, attracting neutrophils that release enzymes causing tissue damage

Question 19

Which equation represents the formation of a provirus during HIV infection?

Accepted Answer

$$	ext{Viral RNA} \xrightarrow{	ext{Reverse transcriptase}} 	ext{Viral DNA} \xrightarrow{	ext{Integrase}} 	ext{Provirus}$$

Question 20

Which of the following is a privileged site where transplants are less likely to be rejected?

Accepted Answer

Cornea

Immune Deficiency Diseases and Hypersensitivity: Mechanisms, Disorders, and HIV/AIDS

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