MCQ Immunology: Antibodies with Answers

Last updated on June 6th, 2021

Immunoglobulins, also known as antibodies are glycoprotein molecules produced by effector B cells (plasma cells). By now, you might have accumulated vast knowledge about these antibodies, their structural differences, functional differences, unique features and applications in diagnostics.

In this set of 10 MCQs about antibodies, you can find questions related with different properties of antibodies. Take a copy and a pencil, and write down answers of each questions as you proceed. At the end of this post, you will get answer key with descriptions. Check your answer with the given answer keys and keep improving your understanding.

  1. Which of the following antibody is an important host defense against encapsulated bacteria?
    a. IgG1
    b. IgG2
    c. IgG3
    d. IgG4
  2. Which of the following immunoglobulin is the most abundant immunoglobulin in newborns?
    a. IgA
    b. IgM
    c. IgG
    d. IgD
  3. Whch of the following immunoglobulin is produced early in the primary response to infection?
    a. IgE
    b. IgA
    c. IgG
    d. IgM
  4. Which of the following immunoglobulin is the main host defense against parasititc infections?
    a. Secretory IgA
    b. IgG
    c. IgM
    d. IgE
  5. Which of the following immunoglobulin has the highest avidity of the immunoglobulins?
    a. IgA
    b. IgM
    c. IgE
    d. IgG
  6. The order of percent of total immunoglobulin in serum is,
    a. IgM, IgA, IgG, IgD, IgE
    b. IgG, IgA, IgM, IgE, IgD
    c. IgG, IgA, IgM, IgE, IgD
    d. IgG, IgA, IgM, IgD, IgE
  7. Which of the following antibody is prominent antigen receptor expressed on B Cells?
    a. IgG
    b. IgA
    c. IgM
    d. IgE
  8. The antibody which is found in secretions is:
    a. IgD
    b. IgE
    c. IgG
    d. IgA
  9. Which of the following antibody directly take part in opsonization process?
    a. IgM
    b. IgG
    c. IgA
    d. IgE
  10. Complement fixation is one of the most important host defense against infections. The complement is activated by;
    a. IgM Only
    b. IgG only
    c. both IgM and IgG
    d. all five classes of antibodies activate complements.  

1. b: IgG2
The IgG2-subclass deficiency is associated with a diminished immune response to (bacterial capsular) polysaccharide antigens.
2.c (IgG).
IgG can cross the placenta and establish passive immunity. Infants also get secretory IgA (SIgA) via breast feeding.
3. d (IgM)
Immunoglobulin M (IgM) antibodies are produced as a body’s first response to a new infection. 
4. d (IgE)
IgE is involved in allergic reactions and immune response to helminths and protozoan pathogens. 
5. b (IgM)
Avidity is a measure of the total binding strength. As IgM can exist as pentameric form, it has highest avidity.
6. d (IgG> IgA >IgM > IgD >IgE)
About 70-80% of the immunoglobulins in the blood are IgG and IgE is the least abundant immunoglobulin in the serum.
7. c (IgM).
Mature B cells have both immunoglobulin M (IgM) and IgD types of BCRs and IgM type BCRs are more common.
8. d (IgA)
Immunoglobulin A (IgA) often exists in a monomeric state when in the bloodstream but it is secreted into the lumen of mucosal surfaces in a dimeric form. IgA can be found in saliva, tears, respiratory, gastrointestinal, and genitourinary secretions.
9. b (IgG)
Opsonization of bacteria takes place when immunoglobulin G (IgG) molecules bind to specific epitopes on bacterial surface antigens through the antigen-binding site leaving the Fc region exposed. Phagocytes possess Fc gamma receptors and therefore can bind to the Fc-coated bacteria and internalize them.
10. c (both IgM and IgG)

Related Posts

 MCQ Immunology 1

MCQ Immunology 2 

MCQ Immunology 3

 MCQ Immunology: Antibodies

About Acharya Tankeshwar 474 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.