• Home
  • Textbooks
  • The Immune System
  • Immunity Mediated by B Cells and Antibodies

The Immune System

Peter Parham

Chapter 9

Immunity Mediated by B Cells and Antibodies - all with Video Answers

Educators

Chapter Questions

07:04

Problem 1

Cross-linking of immunoglobulin by antigen is essential but not always sufficient to initiate the signal cascade for B-cell activation. Involvement of the B-cell co-receptor is also necessary for the full activation and differentiation of naive B cells. Describe this receptor and its ligand and explain how it facilitates B-cell activation.

Charles Kirschbaum
Charles Kirschbaum
Numerade Educator
07:04

Problem 2

All of the following are associated with B-cell activation except $\qquad$
a. close association with complement receptor 1 (CR1), CD19, and CD81
b. clustering of surface immunoglobulin
c. activation of cytoplasmic protein tyrosine kinases
d. participation of cytoplasmic tails of $\operatorname{Ig} \alpha$ and $\operatorname{Ig} \beta$
e. ITAM phosphorylation.

Charles Kirschbaum
Charles Kirschbaum
Numerade Educator
02:22

Problem 3

A. Explain how a B cell that has recently recognized its specific antigen becomes trapped in the lymph node at the boundary of the T-cell and B-cell zones.
B. Why is this necessary with respect to B-cell activation?

Evey Z
Evey Z
Numerade Educator

Problem 4

Follicular dendritic cells produce __________ , which are needed for rapid B-cell proliferation and differentiation into centroblasts.
a. CD40 ligand and IL-4
b. TNF- $\alpha$, LT- $\alpha$, and LT- $\beta$
c. CCL21 and CCL19
d. CD44, CD38, and CD77
e. BAFF, IL-15, IL-6, and 8D6.

Check back soon!
02:21

Problem 5

Individuals born without a thymus _________ _.
a. are unable to make antibodies
b. have similar B-cell function to someone who possesses a thymus
c. have elevated levels of IgG compared with IgM
d. have abnormally reduced numbers of $B$ cells
e. do not mediate effective isotype switching in their B cells.

Justin Im
Justin Im
Numerade Educator
01:45

Problem 6

Which of the following are properties of plasma cells that are not shared with naive B cells? (Select all that apply.)
a. no surface immunoglobulin expression
b. elevated levels of MHC class II expression on the cell surface
c. high rate of immunoglobulin secretion
d. can be induced to switch isotype
e. can be induced to undergo cellular proliferation.

Joanna Quigley
Joanna Quigley
Numerade Educator
03:21

Problem 7

Which of the following is incorrect regarding the Fc receptor FcaRI?
a. It is a medium-affinity receptor.
b. It requires the common $\gamma$ chain to mediate signaling.
c. It binds to dimeric IgA.
d. It is encoded on a different chromosome from the genes encoding the Fc receptors for $\mathrm{IgG}$ and $\mathrm{IgE}$.
e. It mediates the phagocytosis of pathogens coated with IgA.

Joanna Quigley
Joanna Quigley
Numerade Educator

Problem 8

Match the receptor in column A with its description in Column B.
$$
\begin{array}{|l|l|}
\hline \text { Column A } & \text { Column B } \\
\hline \begin{array}{l}
\text { a. poly-Ig } \\
\text { receptor }
\end{array} & \begin{array}{l}
\text { 1. transports IgG out of the bloodstream to } \\
\text { extracellular spaces in tissues }
\end{array} \\
\hline \begin{array}{l}
\text { b. FcyRIII } \\
\text { (CD16) }
\end{array} & \begin{array}{l}
\text { 2. facilitates antibody-dependent cell- } \\
\text { mediated cytotoxicity in NK cells }
\end{array} \\
\hline \text { c. FceRI } & \begin{array}{l}
\text { 3. cross-links antibody:antigen complexes on } \\
\text { mast cells followed by degranulation }
\end{array} \\
\hline \text { d. FcRn } & \begin{array}{l}
\text { 4. binds to dimeric IgA and facilitates its } \\
\text { transcytosis }
\end{array} \\
\hline \begin{array}{l}
\text { e. B-cell } \\
\text { co-receptor }
\end{array} & \text { 5. CD21/CD19/CD81 } \\
\hline \begin{array}{l}
\text { f. FcyRII-B1 } \\
\text { (CD32) }
\end{array} & \text { 6. inhibition of B-cell activation } \\
\hline
\end{array}
$$

Check back soon!
00:35

Problem 9

Mucosal epithelia of the gastrointestinal tract, eyes, nose, throat, the respiratory, urinary, and genital tracts, and the mammary glands are protected by
a. IgG
b. IgM
c. IgE
d. monomeric IgA
e. dimeric IgA.

Patsy Naomi
Patsy Naomi
Numerade Educator
03:21

Problem 10

Which of the following accounts for the relatively low levels of IgE in the circulation?
a. Isotype switching to IgE is a relatively rare event in germinal centers.
b. IgE is rapidly degraded by serum proteases.
c. FcRn binds with high affinity to IgE and ushers it into extracellular fluids of connective tissues.
d. IgE is rapidly phagocytosed by neutrophils whether or not it is bound to antigen.
e. IgE binds with high affinity to mast cells, basophils, and activated eosinophils in the absence of antigen.

Joanna Quigley
Joanna Quigley
Numerade Educator
00:59

Problem 11

The poly-Ig receptor on the basolateral surface of epithelial cells binds to ________ via the __________ . (Select all that apply.)
a. dimeric IgA; J chain
b. monomeric IgA; J chain
c. monomeric IgA; CH2 domain
d. IgM; J chain
e. IgG; CH3 domain.

Asma Venkitta
Asma Venkitta
Numerade Educator

Problem 12

Which of the following are examples of passive transfer of immunity? (Select all that apply.)
a. antibody production after vaccination
b. transplacental acquisition of IgG during fetal development
c. provision of IgA through breast milk
d. antibody production after an influenza infection
e. intravenous immunoglobulin therapy for immunocompromised individuals
f. receiving antivenom after being bitten by a poisonous snake.

Check back soon!
00:27

Problem 13

Erythrocytes are equipped to facilitate the removal of small immune complexes from the circulation using receptors that bind to _______
a. IgG
b. Clq
c. C3b
d. CR2
e. F-protein.

Ashley Thompson
Ashley Thompson
Numerade Educator
03:51

Problem 14

A. Explain how the receptor FcRn transports IgG antibodies across cellular barriers, and specify the type of cell barrier involved.
B. What is the final location of transported material?

Sana Riaz
Sana Riaz
Numerade Educator

Problem 15

Anthony Hoffnagle was well until 6 months of age, when he was hospitalized for pneumonia. In the following year he was hospitalized five times for additional episodes of pneumonia, septic arthritis, and febrile convulsion. Yesterday, Anthony was diagnosed with pneumonia caused by Pneumocystis jirovecii, and consultation with an immunologist was requested. Anthony's tests revealed neutropenia, normal numbers of $\mathrm{B}$ cells and T cells, slightly elevated IgM, but a marked decrease in IgG and IgA compared with normal. Autoantibodies against neutrophils were not detected. Liver function tests were normal. Bone marrow aspiration indicated severe maturational arrest of the myeloid lineage at the promyelocyte-myelocyte stage. A diagnosis of X-linked hyper-IgM syndrome (XHIGM) was made. Anthony's parents were informed that their son would require long-term treatment with intravenous immunoglobulin (IVIG), prophylactic antibiotics, and periodic injection of granulocyte colony-stimulating factor (G-CSF) for episodes of neutropenia. Genetic analysis of the gene encoding_________ revealed a frameshift and stop codon mutation causing aberrant transcription of this gene.
a. CD40 ligand
b. CD3
c. CD19
d. RAGI
e. CD81.

Check back soon!