Deck 5: Antibody Structure and Function

Question 1

Which of the following is a characteristic of IgA?

A) It is found in secretions.
B) It fixes complement.
C) It is a pentamer in serum.
D) It is the primary response antibody.

Answer 1

It is found in secretions.

Question 2

Which region of the immunoglobulin molecule can bind antigen?

A) Fab
B) CL
C) CH
D) Hinge region

Answer 2

Fab

Question 3

Identify the correct pairing of an immunoglobulin and its property.

A) IgA: crosses the placenta
B) IgG: most abundant in serum
C) IgM: immunoglobulin produced by a T cell
D) IgE: major immunoglobulin of secondary response

Answer 3

IgG: most abundant in serum

Question 4

The antigen specificity of a B cell is determined:

A) after interaction with antigen.
B) by H- and L-chain variable-region sequences.
C) only by the L chain.
D) after isotype switching.

Question 5

Which immunoglobulin is found in only trace amounts in the serum?

A) IgM
B) IgG
C) IgD
D) IgA

Question 6

The idiotype of an antibody is located on which region?

A) CH
B) CL
C) VH + VL
D) Fc

Question 7

Kappa or lambda light chains:

A) are encoded on the same chromosome.
B) associate with only one type of heavy chain at a time.
C) can be expressed by the same B cell.
D) are expressed by a pre-B cell.

Question 8

The ability of an antibody to opsonize is located in which region?

A) F(ab)₂
B) Fc
C) VL + VC
D) Hypervariable

Question 9

Variations in immunoglobulin structure that occur because of the use of different constant region domains are known as:

A) allotypes.
B) idiotypes.
C) isotypes.
D) autotypes.

Question 10

The primary response is characterized by:

A) the recognition of antigens by naïve B cells.
B) the recognition of antigens by memory B cells.
C) the production of large amounts of IgG.
D) a very short lag period.
E) a long duration of high titer.

Question 11

Which immunoglobulin can cross the placenta?

A) IgM
B) IgE
C) IgA
D) IgG

Question 12

Which immunoglobulin appears in the highest titer in the secondary response?

A) IgG
B) IgA
C) IgM
D) IgD

Question 13

Identify the true statement about the anamnestic response versus the primary response.

A) The primary response has a long lag phase; the anamnestic response has a short lag phase.
B) The primary response has a short lag phase; the anamnestic response has a long lag phase.
C) the primary response involves a rapid increase in antibody titer, whereas the anamnestic response involves a rapid decrease in antibody titer.
D) The primary response involves predominantly an increase in IgG antibodies, whereas the anamnestic response involves predominantly an increase in IgM antibodies.

Question 14

Which immunoglobulin activates the classical complement pathway?

A) IgD
B) IgM
C) IgA
D) IgE

Question 15

Which is characteristic of IgG?

A) First class of antibody to appear
B) Found mainly in secretions
C) The least abundant antibody in serum
D) Provides immunity for the newborn

Question 16

What products are the result of papain being used to cleave antibody molecules?

A) Two Fab fragments and one Fc portion
B) Two L chains and two H chains
C) VL, CL, VH, and CH
D) One F(ab)₂ and Fc' portions

Question 17

Which is a characteristic of IgM?

A) It can cross the placenta.
B) It is able to fix complement.
C) It increases greatly in the secondary response.
D) It can bind only two antigens.

Question 18

Which of the following pairs represents light chains of antibody molecules?

A) Kappa and epsilon
B) Gamma and lambda
C) Lambda and kappa
D) Alpha and beta

Question 19

All polymeric but not monomeric immunoglobulins are characterized by:

A) a secretory component.
B) an extra H-chain domain.
C) a J chain.
D) high carbohydrate content.

Question 20

Which immunoglobulin appears first in the primary response?

A) IgG
B) IgM
C) IgA
D) IgE

Question 21

The combination of a plasma cell fused to a myeloma cell is called a:

A) melanoma.
B) hybridoma.
C) mycetoma.
D) myeloma.

Question 22

IgA in secretions has a valence of:

A) 1.
B) 2.
C) 4.
D) 10.

Question 23

The valence of an IgG antibody molecule is:

A) 1.
B) 2.
C) 4.
D) 10.

Question 24

Which of the following statements about coding for antibody molecules is true?

A) Heavy chains are coded for on chromosome 2.
B) V, D, and J code for heavy chain variable regions.
C) DNA molecules coding for light chains are rearranged first.
D) V and D code for light chain variable regions.

Question 25

Immunoglobulins are grouped into classes on the basis of similarities in:

A) light chains.
B) heavy chains.
C) antigen binding sites.
D) disulfide bonds.

Question 26

Which immunoglobulin causes allergic reactions as a result of release of histamine from mast cells?

A) IgA
B) IgE
C) IgD
D) IgM

Question 27

Which class makes up 70% to 80% of total serum immunoglobulins?

A) IgA
B) IgG
C) IgM
D) IgE

Question 28

A Fab fragment consists of:

A) two heavy chains.
B) two light chains.
C) one light chain and one-half of a heavy chain.
D) one light chain and an entire heavy chain.

Question 29

Identify the statement about monoclonal antibodies that is true.

A) They all recognize numerous antigens.
B) They arise from a single B cell.
C) They are used for testing only and not as therapeutic agents.
D) They are found only in cancerous states.

Question 30

Which option best describes monoclonal antibody?

A) Antibody made against multiple epitopes
B) Antibody made by a variety of B cells
C) Antibody made from a single antibody-producing cell
D) All antibody of any one particular class

Question 31

Select the statement about secondary response to an antigen that is true.

A) Equal amounts of IgM and IgG are made.
B) IgG is increased 100-fold to 1,000-fold.
C) IgM is increased 100-fold.
D) The lag time is the same as the primary response.

Question 32

Somatic mutation of immunoglobulin genes accounts for:

A) allelic exclusion.
B) class switching from IgM to IgG.
C) affinity maturation.
D) creation of the isotype.

Question 33

Which option represents an isotype of a heavy chain?

A) Kappa
B) Beta
C) Epsilon
D) Lambda

Question 34

The receptor for antigen on a mature B cell is:

A) MHC class I.
B) IgG.
C) IgM.
D) MHC class II.

Question 35

What is the main function of IgD?

A) It helps in class switching.
B) It is a primary response antibody.
C) It protects mucous membranes.
D) It offers protection to newborns.

Question 36

Which antibody is best able to agglutinate and fix complement?

A) IgA
B) IgM
C) IgG
D) IgE

Question 37

The region of an antibody molecule that exhibits the greatest variability from antibody to antibody is known as the:

A) hypervariable region.
B) constant region.
C) Fc region.

Question 38

Bence-Jones proteins are identical to:

A) secretory IgA.
B) heavy chains.
C) light chains.
D) IgG molecules.

Question 39

Immunoglobulins IgG,IgM,IgA,and IgD represent:

A) isotypes.
B) allotypes.
C) idiotypes.
D) heterotypes.

Question 40

IgD is produced by:

A) differential splicing of the RNA transcript.
B) differential splicing of the DNA transcript.
C) constant gene-region rearrangement.
D) immature B cells.

Question 41

Of all IgG subclasses,IgG3 has the largest hinge region,making it:

A) the only subclass capable of crossing the placenta.
B) the subclass with the highest number of antigen binding sites.
C) the most efficient subclass for activating complement.
D) incapable of opsonization.

Question 42

Identify the main purpose of the secretory component of IgA.

A) Transports across endothelial cells
B) Combines with antigen
C) Joins the two monomers
D) Involved in class switching

Question 43

IgG subclasses differ from one another in the number and position of:

A) heavy chain domains.
B) antigen binding sites.
C) light chains.
D) disulfide bonds.

Question 44

The antibody found on B cells that is thought to be involved in B-cell maturation is:

A) IgA.
B) IgD.
C) IgE.
D) IgM.

Question 45

In serum electrophoresis conducted at pH 8.6,which protein group migrates the fastest?

A) Albumin
B) Alpha-1 globulin
C) Alpha-2 globulin
D) Gamma globulin

Question 46

Identify the characteristic that best describes IgE.

A) Fixes complement
B) Binds to mast cells
C) Found on mucosal surfaces
D) Participates in agglutination reactions

Question 47

In serum protein electrophoresis,which band contains the immunoglobulins?

A) Alpha-1
B) Alpha-2
C) Beta
D) Gamma

Question 48

The antibody that appears first in an immune response and is a pentamer with a molecular weight of 900,000 Da best describes:

A) IgM.
B) IgD.
C) IgA.
D) IgG.

Question 49

Which antibody is found mainly as a dimer in mucosal secretions?

A) IgA
B) IgD
C) IgE
D) IgG

Question 50

Where on an antibody molecule does combination with antigen take place?

A) Variable region
B) Constant region
C) Hinge region
D) Fc region

Question 51

Which of the following best characterizes IgD?

A) Primary response antibody
B) Surface receptor for antigen
C) Responsible for allergic reactions
D) Fixes complement

Question 52

The theory that lymphocytes are preprogrammed to respond to a particular type of antigen best describes:

A) the clonal selection theory.
B) Ehrlich's side-chain theory.
C) the spontaneous generation theory.
D) Edelman's antibody-formation theory.

Question 53

How does IgG differ from IgM?

A) IgM can cross the placenta.
B) IgG can bind more antigens than IgM.
C) IgG is the main antibody in serum.
D) Only IgM has kappa light chains.