Exam 2

Question 1

With the exception of B cells, all other cells of the body have the immunoglobulin genes in the ______________.

Answer 1

Germline configuration

Question 2

If viewing the three-dimensional structure of a T-cell receptor from the side, with the T-cell membrane at the bottom and the receptor pointing upwards, which of the following is inconsistent with experimental data?

Answer 2

The portion that makes physical contact with the ligand comprises Vbeta and Cbeta, the domains farthest from the T-cell membrane.

Question 3

The mutational mechanism that results in the production of antibodies that bind antigen with higher affinity is called _____.

Answer 3

Somatic hypermutation

Question 4

Unlike the C regions of immunoglobulin heavy-chain loci, the C regions of the T-cell receptor beta-chain loci ______.

Answer 4

Are functionally similar

Question 5

On the heavy-chain immunoglobulin gene locus, recombination signal sequences flank _______ of the V segment, _______ of the D segment, and _______ of the J segment.

Answer 5

The 3-prime side; both sides; the 5-prime side

Question 6

Which of the following cell types is(are) not considered a professional antigen-presenting cell(s)?

Answer 6

Neutrophil

Question 7

The name given to a fully activated and differentiated B cell that secretes antibody is __________________.

Answer 7

Plasma cell

Question 8

In what way does the kappa light chain differ from the lambda light chain?

Answer 8

The kappa locus encodes a single C segment, whereas the lambda locus has more than one

Question 9

The role of the CD3 proteins and zeta chain on the surface of the cell is to ___________________.

Answer 9

Transduce signals to the interior of the T-cell

Question 10

Which of the following describes the sequence of events involved in the processing of peptides that will be presented as antigen with MHC class II?

Answer 10

endocytosis -> protease activity -> removal of CLIP from MHC class II -> binding of peptide to MHC class II -> plasma membrane

Question 11

CD8 T-cell subpopulations are specialized to combat _______ pathogens, whereas CD4 T-cell subpopulations are specialized to combat _______ pathogens.

Answer 11

Intracellular; extracellular

Question 12

Directional selection is best described as ____________.

Answer 12

selected alleles increase in frequency in a population

Question 13

A circulating B cell that has never before encountered antigen expresses _____ on the cell surface.

Answer 13

IgM and IgD

Question 14

Linear epitopes are epitopes in proteins that comprise a contiguous amino acid sequence. They are also called continuous epitopes. In contrast, a conformational epitope is formed by amino acids that are brought together as a result of protein folding and are not adjacent in the protein sequence. Conformational epitopes are also known as discontinuous epitopes.

Answer 14

True

Question 15

Which of the following determines the isotype of an immunoglobulin?

Answer 15

Its heavy chain

Question 16

All of the following processes occur in mature B cells after antigen encounter except:

Answer 16

Somatic recombination

Question 17

Which of the following does not describe B-cell receptors?

Answer 17

B-cell receptors lack specificity and can bind to a number of different antigens.

Question 18

T-cell receptors interact not only with peptide anchored in the peptide-binding groove of MHC molecules, but also with ____________________.

Answer 18

variable amino acid residues on alpha helices of the MHC molecule

Question 19

Which of the following is/are not encoded on chromosome 6 in the HLA complex?

Answer 19

beta2-microglobulin and invariant chain

Question 20

Peptides that bind to a particular MHC isoform usually have either the same or chemically similar amino acids at two to three key positions that hold the peptide tightly in the peptide-binding groove of the MHC molecule. These amino acids are called _____ and the combination of these key residues is known as its _________________.

Answer 20

anchor residues; peptide-binding motif

Question 21

Which of the following characteristics is common to both T-cell receptors and immunoglobulins?

Answer 21

Somatic recombination of V, D, and J segments is responsible for the diversity of antigen-binding sites.

Question 22

MHC class II molecules are made up of two chains called _______, whose function is to bind peptides and present them to _______ T cells.

Answer 22

alpha and beta; CD4

Question 23

As an adaptive immune response progresses, the production of variant antibodies that compete more effectively for antigen occurs, and B cells producing these antibodies are preferentially selected on the basis of their improved binding to antigen. This phenomenon is referred to as _______.

Answer 23

Affinity maturation

Question 24

Which of the following can be found in serum in a monovalent form?

Answer 24

IgG4

Question 25

Which of the following best describes the function of tapasin?

Answer 25

Tapasin is a bridging protein that binds to both TAP and MHC class I molecules and facilitates the selection of peptides that bind tightly to MHC class I molecules.

Question 26

Which of the following statements regarding CD8 T cells is incorrect?

Answer 26

When activated, CD8 T cells in turn activate B cells.

Question 27

The CDR3 loops of the T-cell receptor contact the _______.

Answer 27

side chains of amino acids in the middle of the peptide

Question 28

The enzyme responsible for adding N nucleotides is _______.

Answer 28

terminal deoxynucleotidyl transferase

Question 29

Which of the following is not a characteristic of immunoproteasomes?

Answer 29

They produce a higher proportion of peptides containing acidic amino acids at the carboxy terminus compared with constitutive proteasomes.

Question 30

Which of the following describes two recombination signal sequences required for a permitted somatic recombination event?

Answer 30

DH 7-12-9::9-23-7 JH

Question 31

A newborn derives passive immunity from its mother as a result of placental transfer of _____ during pregnancy.

Answer 31

IgG

Question 32

How many complementarity-determining regions contribute to the antigen-binding site in an intact T-cell receptor?

Answer 32

6

Question 33

Naive B cells are recognized by their expression of ______________.

Answer 33

both IgM and IgD on the cell surface

Question 34

Which of the following is not a term used to describe the molecules or components of molecules to which antibodies bind?

Answer 34

CDR loops

Question 35

Which of the following is mismatched?

Answer 35

four C domains: IgM and IgD

Question 36

In reference to the interaction between T-cell receptors and their corresponding ligands, which of the following statements is correct?

Answer 36

The most variable part of the T-cell receptor is composed of the CDR3 loops of both the alpha and beta chains.

Question 37

_____, _____, and _____ are the three most abundant antibodies in blood:

Answer 37

IgA, IgG, and IgM

Question 38

Which of the following statements regarding Omenn syndrome is incorrect?

Answer 38

It is the consequence of complete loss of RAG function.

Question 39

Which of the following is not a characteristic of native antigen recognized by T cells?

Answer 39

not requiring degradation for recognition

Question 40

Another term commonly used to describe hypervariable loops is ___________.

Answer 40

complementarity-determining regions (CDRs)

Question 41

Which of the following is matched incorrectly?

Answer 41

affinity maturation: addition of P and N nucleotides

Question 42

The highest degree of diversity resulting from somatic recombination is concentrated ____________ of the VH and VL domains, whereas the point mutations caused by somatic hypermutation are found ____________.

Answer 42

in CDR3; throughout the V region

Question 43

Which immunoglobulin is transported most efficiently across mucosal epithelium?

Answer 43

IgA

Question 44

The immunological consequence of severe combined immunodeficiency disease (SCID) caused by a genetic defect in either RAG-1 or RAG-2 genes is _____________________.

Answer 44

lack of somatic recombination in T-cell receptor and immunoglobulin gene loci

Question 45

T cells recognize antigen when the antigen ___________________.

Answer 45

forms a complex with membrane-bound MHC molecules on another host-derived cell

Question 46

Which of the following describes a typical ligand for an alpha:beta T-cell receptor?

Answer 46

peptide:MHC complex

Question 47

Production by the patient of antibodies against therapeutic mouse monoclonal antibodies is the major limitation for their use in humans. These human anti-antibodies are directed against the _____ of the mouse antibody.

Answer 47

C regions

Question 48

An epitope is the specific part of the antigen that is recognized by an antibody and binds to the complementarity-determining regions in the antibody variable domains. Epitopes are sometimes referred to as antigenic determinants. Epitopes can be part of a protein or can be carbohydrate or lipid structures present in the glycoproteins, polysaccharides, glycolipids, and proteoglycans of pathogens.

Answer 48

True

Question 49

IgG possesses _______ binding sites for antigen, and the T-cell receptor possesses _______ binding sites for antigen.

Answer 49

2; 1

Question 50

All of the following are oligomorphic except ___________________.

Answer 50

HLA-DQ beta chain