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FCPS Part 1 Immunology MCQs
Immunology questions test innate and adaptive immunity, antibodies, complement, hypersensitivity reactions, transplant rejection, immunodeficiencies and vaccines.
Below are 5 free single-best-answer questions drawn from the most frequently examined immunology concepts, each with the answer and a rationale for every option. The full bank has 81 immunology concepts, each asked several different ways.
Free immunology questions
Question 1
Induration 48–72 hours after intradermal tuberculin injection reflects which hypersensitivity type?
- A. Type IV
- B. Type V
- C. Type II
- D. Type I
- E. Type III
Show answer
Answer: A. Type IV
Type IV reactions are mediated by sensitised T cells, not antibody. CD4 cells release IFN-gamma to activate macrophages, and the reaction peaks at 48 to 72 hours.
Why not the others: Type I: IgE-mediated immediate reaction. Type II: antibody against cell surface antigens. Type III: immune complex deposition. Type V: antibody stimulating receptors, as in Graves disease.
High-yield: Type IV = T cell, delayed: tuberculin, contact dermatitis, GVHD.
Question 2
Immunoglobulin class that crosses the placenta to give the neonate passive immunity:
- A. IgG
- B. IgA
- C. IgD
- D. IgM
- E. IgE
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Answer: A. IgG
IgG is the main secondary-response antibody and about three quarters of serum immunoglobulin. Its small size and placental Fc transport allow transfer to the fetus, and it opsonises and fixes complement.
Why not the others: IgA: mucosal secretions, does not cross placenta. IgM: pentamer too large to cross. IgE: mast cell degranulation in allergy. IgD: surface receptor on naive B cells.
High-yield: Only IgG crosses the placenta; IgM is first; IgA is secreted.
Question 3
Macrophage cytokine acting on the hypothalamus to produce fever:
- A. IL-1
- B. IL-4
- C. IL-2
- D. IL-12
- E. IL-10
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Answer: A. IL-1
IL-1 from macrophages acts on the hypothalamus to induce prostaglandin E2, raising the thermoregulatory set point and causing fever.
Why not the others: IL-4: Th2, IgE switching. IL-10: anti-inflammatory. IL-12: Th1 differentiation. IL-2: T-cell growth. IL-5: eosinophil growth.
High-yield: Fever: IL-1 (with TNF-alpha and IL-6), via PGE2.
Question 4
Cell lineage that fails to mature in X-linked agammaglobulinaemia from a BTK mutation:
- A. B lymphocytes
- B. Basophils
- C. Macrophages
- D. T lymphocytes
- E. Neutrophils
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Answer: A. B lymphocytes
Bruton tyrosine kinase is needed for B-cell maturation, so mutated BTK leaves no peripheral B cells and low immunoglobulins of every class. Symptoms begin as maternal IgG wanes, and T-cell function is normal.
Why not the others: T lymphocytes: normal in Bruton disease. Neutrophils: normal numbers. Macrophages: normal. Basophils: unaffected. Natural killer cells: innate lymphocytes, unaffected.
High-yield: Bruton: B cells absent, T cells normal, infections after 6 months.
Question 5
Tissue-resident cell storing histamine and heparin in granules:
- A. Eosinophil
- B. Mast cell
- C. Monocyte
- D. Macrophage
- E. Neutrophil
Show answer
Answer: B. Mast cell
Mast cells store histamine with heparin and carry Fc-epsilon receptors. Allergen cross-linking surface IgE triggers degranulation, the basis of type I hypersensitivity.
Why not the others: Eosinophil: parasites and late allergic phase. Neutrophil: acute bacterial inflammation. Macrophage: phagocytosis and antigen presentation. Monocyte: circulating precursor of macrophages. Plasma cell: antibody secretion.
High-yield: Mast cell = tissue histamine, heparin and IgE receptor; basophil is its circulating look-alike.
Keep going with immunology
Anaesgen brings every concept back on a spaced-repetition schedule timed to your exam date, as a different question each time, with full mock papers for Paper 1 and 2.
Get full access Try the 5 sample questionsHigh-yield immunology one-liners
The most-tested immunology concepts, as a clue and the answer it points to:
- Tuberculin, GVHD, contact dermatitis, T-cell, delayed → Type IV.
- Placenta, most abundant, opsonin, anti-D → IgG.
- Macrophage, hypothalamus, PGE2, fever → IL-1.
- BTK, absent immunoglobulins, EBV tropism → B lymphocytes.
- Tissue histamine and heparin, IgE receptors, type I degranulation → mast cell.
- Myeloma, M band, antibody secretion → plasma cells.
- CREST, limited scleroderma, Raynaud + telangiectasia → anti-centromere.
- Live, attenuated M. bovis, avoid in immunodeficiency → BCG.
- Neutrophil chemotaxis, anaphylatoxin → C5a.
- Haemolytic disease of newborn, cord blood → positive direct Coombs with maternal IgG.
- Back pain better with exercise, sacroiliitis, bamboo spine, uveitis → HLA-B27.
- Allergy, anaphylaxis, mast cell Fc receptors, lowest serum level → IgE.
- Boy, absent B cells, all immunoglobulins low, BTK → pro-B to B-cell block.
- Mantoux, cell-mediated immunity, graft rejection → T lymphocytes.
- Atopy, hives within minutes, IgE on mast cells → type I.
- Plasma cells, humoral, specific, memory, classical pathway trigger → antibodies.
- Type 1 diabetes, beta-cell autoimmunity, stiff-person → anti-GAD.
- Goodpasture, haemoptysis plus GN, linear IgG → anti-GBM antibodies.
- Recurrent miscarriage, arterial or venous thrombosis, long APTT → antiphospholipid antibodies.
- NK cell, missing MHC I, perforin/granzyme → destroy virus-infected cells.
Other FCPS Part 1 subjects
AnatomyPharmacologyPathologyBiochemistry & GeneticsCardiovascularNeurophysiologyMicrobiologyHaematologyGeneral PhysiologyEndocrineRespiratoryEmbryologyObstetrics & GynaeRenal & Acid-BaseHistologyGI & LiverPhysicsBiostatistics
New to the exam? Read the FCPS Part 1 exam guide: dates, format and a 12-week study plan.