MCQ in Immunology (71-85): Basic Concepts Answers with Explanation

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 also posted the answers. I expect persons with good exposure to immunology must give correct answers to at least 14 questions; if you fail to do so, please revise immunology once again.

71. 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

72. Which of the following conveys 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

73. Which 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

74. 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

75. 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

76. 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

77. A living microbe with reduced virulence that is used for vaccination is considered:
a. A toxoid
b. Dormant
c. Virulent
d. Attenuated
e. Denatured

78. B cells that produce and release large amounts of antibodies are called:
a. Memory cells
b. Basophils
c. Plasma cells
d. Killer cells
e. Neutrophils

79. 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

80. In agglutination reactions, the antigen is a……… and 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

81. B Cells are activated by
a. Complement
b. Antibody
c. Interferon
d. Memory cells
e. Antigen

82. Fusion between a plasma cell and a tumor cell creates a
a. Myeloma
b. Natural killer cell
c. Lymphoblast
d. Lymphoma
e. Hybridoma

83. Monoclonal antibodies recognize a single:
a. Antigen
b. Bacterium
c. Epitope
d. B cell
e. Virus

84. 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

85. The ability of the immune system to recognize self-antigens versus non-self antigen is an example of:
a. Specific immunity
b. Self-tolerance or immunological tolerance
c. Cell-mediated immunity
d. Antigenic immunity
e. Humoral immunity

Answers of MCQ Immunology: Basic Concepts (71-85)

71. 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 an infectious agent. So the answer is “d”.

72. 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 contains active immunity as a part of the answer. The answer is “c”

73. Hapten is a small molecule; it can act as an antigen if it binds to a larger protein molecule. So the answer is “c”

74. This question asked you which stem cell is the immediate precursor of B Cell and T cell. The early development of stem cells takes place in primitive tissue, a late development in the fetal liver, and final development in the bone marrow. So the answer is “a” i.e. bone marrow.

75. Do you remember the sentence; T cells are thymus-derived cells? If you can remember, you already solved this question. If not you might remember that “differentiation of B Cell takes place in the bone marrow and functional B cells are found in Gut-associated Lymphoid tissue (GALT)”. Yes the right answer is “c”

76. T cytolytic cell Tc cells and Natural killer cells kill infected host cells which are harboring the intracellular pathogen. So the answer is option “e”

77. Attenuated means weakened. While making a live attenuated vaccine the virulence of the microorganism is lost but its antigenic characteristics are retained. The answer is “d”.

78. In this question, the definition is given and the word is asked. The definition of a plasma cell is “B Cell that is capable of producing a large number of antibodies”. So the answer is “c”

79. We know antibodies can bind to only specific antigens. This is the known specificity of the antibodies. The variable portion of the heavy and light chain helps obtain this specificity. Some reports suggest that there are 10,530 types of H-chains and 200 types of L-chains, which can make as many as 2,106,000 different types. So the answer is “d“.

80. Agglutination tests help to detect antibodies or antigens and involve agglutination of bacteria, red cells, or antigen- or antibody-coated latex particles. So, whole cells are involved in the agglutination reaction. In contrast, the precipitation test involves the soluble antigens that bind to specific antibodies. So, the answer to the question is a whole cell/soluble molecule or option “a.”

81. Activating naive lymphocytes (naive T cells and B cells) occurs by binding antigens to specific receptors. So, the antigen binding to the B cell receptor (BCR) triggers signaling cascades, ultimately leading to the activation of the B cell. Therefore, antigen or option “e” is the correct answer.

82. Hybridoma means the fusion of B cells and myeloma. Here, B cells are part of blood or plasma cells, and myeloma means cancerous cells. Therefore, the option “e” is the correct answer.

83. Monoclonal antibodies can bind to only one specific antigen. However, it has to recognize the antigenic determinant or epitope of the antigens. So, the correct choice is option “c“.

84. B lymphocytes are the only cells that can produce antibodies; therefore, they are the cells that mediate humoral immunity. So, T cells are responsible for cell-mediated immunity. The correct option is “c“.

85. Self-tolerance or immunological tolerance prevents the immune system from reacting to self-produced antigens. So, the correct option for this question is “b.”

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