Q.1 Which of the following best describes immunopathology?
Study of infections
Study of immune system disorders
Study of genetic mutations
Study of hormonal regulation
Explanation - Immunopathology deals with diseases caused by abnormal immune responses, including hypersensitivity, autoimmunity, and immunodeficiency.
Correct answer is: Study of immune system disorders
Q.2 Which type of hypersensitivity reaction is mediated by IgE antibodies?
Type I
Type II
Type III
Type IV
Explanation - Type I hypersensitivity (immediate) is mediated by IgE and involves mast cells and basophils, leading to allergies and anaphylaxis.
Correct answer is: Type I
Q.3 Systemic lupus erythematosus (SLE) is primarily an example of which mechanism?
Type I hypersensitivity
Type II hypersensitivity
Type III hypersensitivity
Type IV hypersensitivity
Explanation - SLE is caused by immune complex deposition (Type III), leading to widespread inflammation and tissue damage.
Correct answer is: Type III hypersensitivity
Q.4 Which immune cells are primarily responsible for Type IV hypersensitivity reactions?
B cells
CD8+ T cells
Mast cells
Neutrophils
Explanation - Type IV hypersensitivity (delayed-type) is mediated by T cells, particularly CD8+ cytotoxic T cells and activated macrophages.
Correct answer is: CD8+ T cells
Q.5 Graves’ disease is an example of which type of hypersensitivity?
Type I
Type II
Type III
Type IV
Explanation - In Graves’ disease, antibodies bind to TSH receptors and mimic TSH activity, an example of Type II hypersensitivity.
Correct answer is: Type II
Q.6 Which of the following is NOT a feature of autoimmune diseases?
Loss of self-tolerance
Involvement of immune cells and antibodies
Always inherited genetically
Chronic inflammation
Explanation - Autoimmune diseases may have genetic predispositions, but they are not always inherited. Environmental and immunological factors also contribute.
Correct answer is: Always inherited genetically
Q.7 Which immunoglobulin is most associated with allergic reactions?
IgA
IgG
IgE
IgM
Explanation - IgE binds to allergens and triggers histamine release from mast cells, causing allergic reactions.
Correct answer is: IgE
Q.8 Rheumatoid arthritis primarily involves which hypersensitivity mechanism?
Type I
Type II
Type III
Type IV
Explanation - Rheumatoid arthritis involves immune complex deposition (Type III) and chronic inflammation mediated by T cells.
Correct answer is: Type III
Q.9 Which of the following is a primary immunodeficiency disease?
HIV/AIDS
Diabetes mellitus
Severe Combined Immunodeficiency (SCID)
Tuberculosis
Explanation - SCID is a congenital (primary) immunodeficiency characterized by defective T and B cell function.
Correct answer is: Severe Combined Immunodeficiency (SCID)
Q.10 Which type of hypersensitivity is responsible for contact dermatitis?
Type I
Type II
Type III
Type IV
Explanation - Contact dermatitis is a delayed-type hypersensitivity mediated by T cells (Type IV).
Correct answer is: Type IV
Q.11 Which cytokine is critical for Th1 differentiation?
IL-2
IL-4
IL-12
IL-10
Explanation - IL-12 promotes Th1 differentiation, enhancing cell-mediated immunity against intracellular pathogens.
Correct answer is: IL-12
Q.12 Which immune cells are destroyed in HIV infection?
CD4+ T cells
CD8+ T cells
B cells
Natural killer cells
Explanation - HIV specifically infects and destroys CD4+ T helper cells, leading to immunodeficiency.
Correct answer is: CD4+ T cells
Q.13 Which hypersensitivity reaction involves complement-mediated lysis of cells?
Type I
Type II
Type III
Type IV
Explanation - Type II hypersensitivity involves antibodies binding to cell surfaces and activating complement, leading to cell lysis.
Correct answer is: Type II
Q.14 Which disease is caused by autoantibodies against acetylcholine receptors?
Rheumatoid arthritis
Myasthenia gravis
Graves’ disease
SLE
Explanation - In myasthenia gravis, autoantibodies block acetylcholine receptors at neuromuscular junctions, causing muscle weakness.
Correct answer is: Myasthenia gravis
Q.15 Which diagnostic test detects autoantibodies in systemic lupus erythematosus?
ANA test
ELISA for HIV
Tuberculin skin test
Western blot
Explanation - Antinuclear antibody (ANA) test is commonly used to detect autoantibodies in SLE.
Correct answer is: ANA test
Q.16 Which hypersensitivity is also known as delayed-type hypersensitivity?
Type I
Type II
Type III
Type IV
Explanation - Type IV hypersensitivity is mediated by T cells and takes 24–48 hours to develop.
Correct answer is: Type IV
Q.17 What is the hallmark of Type I hypersensitivity?
Complement activation
Cytotoxic T cell killing
Immune complex deposition
Mast cell degranulation
Explanation - Type I hypersensitivity involves mast cell degranulation releasing histamine and other mediators.
Correct answer is: Mast cell degranulation
Q.18 Which autoimmune disease involves the destruction of pancreatic beta cells?
Type 1 diabetes mellitus
Type 2 diabetes mellitus
Addison’s disease
Multiple sclerosis
Explanation - Type 1 diabetes is an autoimmune disease where immune cells destroy insulin-producing beta cells.
Correct answer is: Type 1 diabetes mellitus
Q.19 Which immunodeficiency is characterized by recurrent bacterial infections due to lack of antibodies?
DiGeorge syndrome
X-linked agammaglobulinemia
SCID
AIDS
Explanation - X-linked agammaglobulinemia results in defective B cell development and absent antibody production.
Correct answer is: X-linked agammaglobulinemia
Q.20 Which hypersensitivity is tested using the Mantoux (tuberculin) skin test?
Type I
Type II
Type III
Type IV
Explanation - The Mantoux test checks for delayed-type hypersensitivity (Type IV) against Mycobacterium tuberculosis antigens.
Correct answer is: Type IV
Q.21 Which complement component is critical in opsonization?
C1q
C3b
C5a
C9
Explanation - C3b binds to pathogens and enhances phagocytosis by immune cells, playing a major role in opsonization.
Correct answer is: C3b
Q.22 Hashimoto’s thyroiditis is an autoimmune disease primarily targeting:
Thyroid gland
Adrenal cortex
Pancreatic islets
Joints
Explanation - Hashimoto’s thyroiditis is an autoimmune condition where the thyroid gland is destroyed by lymphocytic infiltration.
Correct answer is: Thyroid gland
Q.23 Which of the following cells mediate antibody-dependent cell-mediated cytotoxicity (ADCC)?
B cells
CD8+ T cells
Natural killer cells
Macrophages
Explanation - NK cells recognize antibody-coated cells and kill them through ADCC.
Correct answer is: Natural killer cells
Q.24 Which hypersensitivity mechanism is involved in Goodpasture’s syndrome?
Type I
Type II
Type III
Type IV
Explanation - Goodpasture’s syndrome involves antibodies targeting basement membranes in the kidney and lungs, a Type II hypersensitivity.
Correct answer is: Type II
Q.25 Which molecule is essential for antigen presentation to CD4+ T cells?
MHC class I
MHC class II
CD8
Fc receptor
Explanation - CD4+ T cells recognize antigens presented on MHC class II molecules found on antigen-presenting cells.
Correct answer is: MHC class II