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National Licensure Examination for Veterinarians Veterinary Immunology & Serology: practice questions

National Licensure Examination for Veterinarians (NLEV) · Nepal · Nepal Veterinary Council (NVC Act 2055 BS)

Original practice questions written to the published syllabus · not past papers
6worked here, free
21written to this exam in this subject
14syllabus units

What this subject covers

Innate and adaptive immunity, antibodies and complement, hypersensitivity, vaccines and the cold chain, and the serological tests used in diagnosis and surveillance.

In the exams: ICAR AICE-JRF core group 06; ICAR AIEEA-PG 13 (Microbiology); NAVLE health maintenance and prevention 35%

Where the 21 questions fall

How our questions for National Licensure Examination for Veterinarians spread across the units of Veterinary Immunology & Serology. Difficulty: 12 easy, 9 medium, 0 hard.

Adaptive immunity2
Immunoglobulins2
Vaccine types2
The vaccine cold chain2
Serological tests: ELISA and agglutination2
Serological tests: CFT, AGID and virus neutralisation2
Immunopathology2
Innate immunity1
Antigens and antibodies1
Complement1
The major histocompatibility complex1
Hypersensitivity1
Adjuvants1
Colostral immunity1

6 practice questions, worked

Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.

1 · Adaptive immunity · medium

Which transcription factor identifies regulatory T cells?

  1. T-bet
  2. GATA-3
  3. RORγt
  4. FoxP3
Answer and working

D. FoxP3

FoxP3 defines regulatory T cells. T-bet drives Th1, GATA-3 Th2 and RORγt Th17 differentiation; students often confuse the lineage-defining factors.

Further reading: Tizard IR, Veterinary Immunology, 10th ed.

2 · Antigens and antibodies · easy

The overall binding strength of a multivalent antibody to a multivalent antigen is called:

  1. Avidity
  2. Affinity
  3. Specificity
  4. Valency
Answer and working

A. Avidity

Avidity is the total strength of multivalent binding; affinity is the strength of a single binding site for a single epitope. Pentameric IgM has modest affinity but high avidity.

Further reading: Tizard IR, Veterinary Immunology, 10th ed.

3 · Hypersensitivity · medium

Purpura haemorrhagica in horses following Streptococcus equi infection is classified as a:

  1. Type III (immune complex) hypersensitivity
  2. Type I hypersensitivity
  3. Type II (cytotoxic) hypersensitivity against platelets
  4. Type IV hypersensitivity
Answer and working

A. Type III (immune complex) hypersensitivity

Purpura haemorrhagica is an immune-complex vasculitis involving streptococcal M protein and antibody deposited in vessel walls. It is not IgE-mediated and not primarily an antiplatelet reaction.

Further reading: Tizard IR, Veterinary Immunology, 10th ed.

4 · Vaccine types · medium

In a vaccine trial, the attack rate was 40% in unvaccinated calves and 8% in vaccinated calves. Vaccine efficacy is:

  1. 80%
  2. 32%
  3. 20%
  4. 5-fold
Answer and working

A. 80%

Efficacy = (ARU − ARV) ÷ ARU = (0.40 − 0.08) ÷ 0.40 = 0.80 = 80%. 32% is the absolute difference in percentage points, not efficacy; 20% is ARV ÷ ARU; '5-fold' is the relative risk inverted, not efficacy.

Further reading: Thrusfield M et al., Veterinary Epidemiology, 4th ed.

5 · The vaccine cold chain · medium

Why should ice packs be 'conditioned' before packing freeze-sensitive vaccines in a cold box?

  1. Conditioning sterilises the outside of the packs
  2. Conditioning makes the packs even colder, so they can keep the vaccine cool for longer in transit
  3. Packs straight from the freezer are well below 0 °C and can freeze vaccine touching them
  4. Unconditioned packs cannot be reused
Answer and working

C. Packs straight from the freezer are well below 0 °C and can freeze vaccine touching them

Conditioning means leaving frozen packs until the ice begins to melt and moves inside, so the pack is near 0 °C and will not freeze vaccines. It warms rather than cools the pack slightly.

Further reading: WHO guidance on vaccine temperature sensitivity and the Shake Test

6 · Immunopathology · easy

Bovine leucocyte adhesion deficiency (BLAD) in Holstein cattle is due to a defect in:

  1. MHC class I
  2. Complement C3 (as in Brittany spaniels)
  3. CD18 (β2 integrin)
  4. Immunoglobulin heavy chain
Answer and working

C. CD18 (β2 integrin)

The CD18 defect stops neutrophils adhering to endothelium and leaving blood, so calves show persistent marked neutrophilia yet recurrent infections.

Further reading: Tizard IR, Veterinary Immunology, 10th ed.

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Read the subject

Veterinary Immunology & SerologyThe full study manual, free National Licensure Examination for VeterinariansFormat, sections and how it has changed

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Veterinary Immunology & Serology for other exams

ICAR AICE-JRF/SRF · IndiaENADE · BrazilNational Veterinary Examination · JapanICAR AIEEA · IndiaNational Practising Veterinarian Qualification Examination · ChinaVeterinarian National Examination · South KoreaVeterinarian Licensure Examination · PhilippinesSAVC Registration Examination · South Africa

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