Question 1

During the anamnestic response, IgM-producing plasma cells switch to producing which type of antibody?&#10;A) IgA&#10;B) IgD&#10;C) IgE&#10;D) IgG

Accepted Answer

During the anamnestic response, class switching takes place to the higher affinity IgG antibodies. g-Chain constant regions replace the IgM constant regions. Large concentrations of high affinity IgG appear in the serum in 1 to 3 days after exposure to antigen.

Question 2

The monomeric form of this antibody inserted into the B cell membrane serves as the B cell receptor (BCR):&#10;A) IgA&#10;B) IgE&#10;C) IgG&#10;D) IgM

Accepted Answer

The monomeric form of IgM inserted into the B cell membrane serves as the B cell receptor (BCR). The membrane form of IgM has a CH4 region, a transmembrane region, and a short cytoplasmic region, which are unique to this form of IgM.

Question 3

A patient has numerous skin lesions, including boils and abscesses, and has Staphylococcus aureus-induced lung disease. The patient also has coarse facial features and skeletal abnormalities. The patient exhibits high levels of IgE in the serum. The patient is most likely suffering from:

A) Job syndrome
B) Multiple myeloma
C) Waldenstrom's macroglobulinemia
D) Common variable immunodeficiency (CVID)

Job syndrome

Accepted Answer

Job syndrome is due to a T cell defect that reverses the normal ratio of T helper 1 to T helper 2 cells. The number of T helper 2 cells is inordinately high, causing class switching to IgE production. The syndrome results in a group of signs and symptoms, including coarse facial features, skeletal, connective tissue, and dental abnormalities, a variety of skin lesions, and lung disease caused by S. aureus.

Question 4

Antibodies with high affinity will be able to:&#10;A) Tightly bind lower concentrations of antigen and quickly eliminate infection&#10;B) Tightly bind higher concentrations of antigen and quickly eliminate infection&#10;C) Loosely bind to lower concentrations of antigen and slowly eliminate infection&#10;D) Loosely bind to higher concentrations of antigen and slowly eliminate infection

Accepted Answer

Antibodies with high affinity will tightly bind lower concentrations of microbes and quickly terminate an infection. Antibodies with low affinity loosely bind to higher concentrations of microbes and slowly eliminate infection.

Question 5

A patient has bone pain, high calcium levels, high immunoglobulin levels, and Bence Jones proteins in their urine. The most likely diagnosis for this patient is:&#10;A) Job syndrome&#10;B) Multiple myeloma&#10;C) Waldenstrom's macroglobulinemia&#10;D) Common variable immunodeficiency (CVID)

Accepted Answer

Multiple myeloma is a disorder resulting from clonal production of plasma cells from one B cell. This over-production of plasma cells leads to high levels of one type of immunoglobulin, plasma cell masses in the bone marrow, and bone lesions due to the induction of osteoclasts. The osteoclast induction and subsequent reabsorption of calcium from the bone leads to high serum calcium levels. Also, free antibody light chains, known as Bence Jones proteins, can be found in the urine.

Question 6

Which region of the antibody is important for physical flexibility of the antigen binding region?&#10;A) J chain&#10;B) Hinge region&#10;C) Secretory piece&#10;D) Variable regions

Accepted Answer

The hinge region is the part of the CH2 region that contains a disulfide bond and allows the antibody the flexibility it needs to be able to bind to antigens of different sizes. The J chain is part of the IgM antibody and allows binding to the receptor that transports secretory IgM across epithelial cells, and also allows for attachment of the secretory piece that protects secretory IgM from enzymatic degradation. The variable regions of both light and heavy chains are the portions of the antibody that bind to antigen.

Question 7

Which of the following antibody regions is involved in antigen binding?
I. Light chain variable region
II. Heavy chain variable region
III. Heavy chain constant region

A) I only
B) III only
C) I and II
D) II and III
E) I, II, and III

Accepted Answer

The variable regions from both the heavy and light chains make up the antigen-binding regions of antibodies. The constant regions are in the distal portions of the antibody away from the antigen-binding area.

Question 8

Which class of antibody causes the release of histamine-containing granules of basophils and mast cells?&#10;A) IgA&#10;B) IgE&#10;C) IgG&#10;D) IgM

Accepted Answer

The IgE antibody has a unique CH4 region that allows high affinity Fc receptors on basophils and mast cells to bind to this region on IgE. Cross-linking of IgE bound to Fc receptors causes the release of histamine-containing granules from basophils and mast cells, leading to an allergic reaction and the symptoms of swelling caused by increased vascular permeability and itching.

Question 9

Fab fragments can be used clinically to treat:&#10;A) Job syndrome&#10;B) Digoxin overdose&#10;C) Multiple myeloma&#10;D) Common variable immunodeficiency (CVID)

Accepted Answer

Fab fragments are used in the treatment of digoxin overdose and snake bites. The Fab fragments bind and neutralize the drug or venom component. Then the drug or venom cannot exert a toxic effect and can be eliminated from the body, usually in the urine due to the small size.

Question 10

An IgG2 subclass response is important for proper immunization with the meningococcal vaccine because:&#10;A) IgG2 responds better to protein antigens&#10;B) IgG2 responds better to carbohydrate antigens&#10;C) Other IgG subclasses do not activate complement as efficiently&#10;D) Other IgG subclasses are not always induced following vaccination

Accepted Answer

The organisms that cause meningitis have a carbohydrate-rich capsule, and IgG2 subclasses respond strongly to carbohydrate antigens. Therefore, the IgG2 response provides a stronger primary response, which will make memory cells to provide a stronger secondary response in case of subsequent exposure to the organism.

Deck 9: Antibodies