MCQ in Immunology: Answers with Explanation

Last updated on June 6th, 2021

This is the collection of some multiple-choice questions to check your understanding of immunology;  definitions, terms, concepts, etc. At the end of these Immunology MCQs, I have posted the answers also. I expect persons who have good exposure to immunology must give correct answers at least for 14 questions, if you failed to do so, please revise immunology once again.

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  1. Naturally acquired active immunity would be most likely acquired through which of the following processes?
    a. vaccination
    b. drinking colostrum
    c. natural birth
    d. infection with disease-causing organism followed by recovery.
  2. Which of the following convey the longest-lasting immunity to an infectious agent?
    a. Naturally acquired passive immunity
    b. Artificially acquired passive immunity
    c. Naturally acquired active immunity
    d. All of these
    e. None of these
  3. Which of the following substances will not stimulate an immune response unless they are bound to a larger molecule?
    a. Antigen
    b. Virus
    c. Hapten
    d. Miligen
    e. Antibody
  4. B and T cells are produced by stem cells that are formed in:
    a. Bone marrow
    b. The liver
    c. The circulatory system
    d. The spleen
    e. The lymph nodes
  5. B cells mature in the……….. while T cells mature in the
    a. Thymus/bone marrow and gut-associated lymphoid tissue (GALT)
    b. Spleen/bone marrow and GALT
    c. Bone marrow and GALT/Thymus
    d. Liver/Kidneys
  6. Which of the following immune cells/molecules are most effective at destroying intracellular pathogens?
    a. T helper cells
    b. B cells
    c. Antibodies
    d. Complement
    e. T cytolytic cells
  7. A living microbe with reduced virulence that is used for vaccination is considered:
    a. A toxoid
    b. Dormant
    c. Virulent
    d. Attenuated
    e. Denatured
  8. B cells that produce and release large amounts of antibody are called:
    a. Memory cells
    b. Basophils
    c. Plasma cells
    d. Killer cells
    e. Neutrophils
  9. The specificity of an antibody is due to
    a. its valence
    b. The heavy chains
    c. The Fc portion of the molecule
    d. The variable portion of the heavy and light chain
  10. In agglutination reactions, the antigen is a………
    in precipitation reactions, the antigen is a……………
    a. whole cell/soluble molecule
    b. Soluble molecule/whole cell
    c. Bacterium/virus
    d. Protein/carbohydrates
    e. Protein/Antibody
  11. B Cells are activated by
    a. Complement
    b. Antibody
    c. Interferon
    d. Memory cells
    e. Antigen
  12. Fusion between a plasma cell and a tumor cell creates a
    a. Myeloma
    b. Natural killer cell
    c. Lymphoblast
    d. Lymphoma
    e. Hybridoma
  13. Monoclonal antibodies recognize a single:
    a. Antigen
    b. Bacterium
    c. Epitope
    d. B cell
    e. Virus
  14. Cell-mediated immunity is carried out by………….. while humoral immunity is mainly carried out by………………..
    a. B cells/T cells
    b. Epitopes/Antigens
    c. T cells/B cells
    d. Antibodies/Antigens
    e. Antibodies/Phagocytes
  15. The ability of the immune system to recognize self-antigens versus nonself antigen is an example of:
    a. Specific immunity
    b. Tolerance
    c. Cell-mediated immunity
    d. Antigenic immunity
    e. Humoral immunity

Answers of MCQ Microbiology: Immunology

  1. It’s the easiest MCQ in microbiology. You have to know only the definition of naturally acquired active immunity. Naturally acquired active immunity is produced when the person is exposed to infectious agent. So the answer is “d”.
  2. Active immunity can last a lifetime or for a period of weeks, months or years, depending on how long the antibodies persist. So only one option in the choice contain active immunity as a part of answer. Answer is “c”
  3. Hapten is a small molecule; they can act as antigen if it binds to a larger protein molecule. So the answer is “c”
  4. This question asked you which stem cell is the immediate precursor of B Cell and T cell. The early development of stem cell takes place in primitive tissue, late development in fetal liver and final development in bone marrow. So the answer is “a” i.e. bone marrow.
  5. Do you remember the sentence; T cells are thymus derived cell? If you can remember, you already solved this question. If not you might remember “differentiation of B Cell takes place in bone marrow and functional B cells are found in Gut associated Lymphoid tissue (GALT)”. Yes the right answer is “c”
  6. T cytolytic cell Tc cells and Natural killer cells kill infected host cells which are harboring intracellular pathogen. So answer is option “e”
  7. Attenuated means weakened. While making live attenuated vaccine the virulence of the microorganism is lost but its antigenic characteristics are retained. The answer is “d”.
  8. In this question definition is given and the word is asked. The definition of plasma cell is “B Cell that is capable of producing large amount of antibodies”. So the answer is “c”

I have only posted the answers to the questions from 9-15, if you have any problem understanding those, leave the comment.  I will post the explanations.

9. The variable portion of heavy and light chain

10.whole cell/soluble molecule

11. Antigen



14.T cells/B cells


Test your understanding in Immunology. Try our dedicated MCQ Quiz section for Immunology. 

About Acharya Tankeshwar 476 Articles
Hello, thank you for visiting my blog. I am Tankeshwar Acharya. Blogging is my passion. I am working as an Asst. Professor and Microbiologist at Department of Microbiology and Immunology, Patan Academy of Health Sciences, Nepal. If you want me to write about any posts that you found confusing/difficult, please mention in the comments below.


  1. Please can you send me MCQ question & answers about clinical Immunology [Rheumatic Diseases]

  2. Hi, It is very nice to see the information provided by you. I need information in the form of MCQ for clinical virology, Bacteriology and Mycology.
    Thank you.

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