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Test Bank for Cellular and Molecular Immunology 8th Edition Abbas / All Chapters 1-20 / Full Complete $15.99   Add to cart

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Test Bank for Cellular and Molecular Immunology 8th Edition Abbas / All Chapters 1-20 / Full Complete

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Test Bank for Cellular and Molecular Immunology 8th Edition Abbas / All Chapters 1-20 / Full Complete

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  • September 13, 2022
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Cellular and Molecular Immunology 8th
Edition Abbas Test Bank
Abbas: Cellular and Molecular Immunology, 8th Edition
Activation of T Lymphocytes

Test Bank

Multiple Choice

1. All of the following protein-protein interactions are involved in activation of naive
helper T cells by antigen-presenting cells (APCs) EXCEPT binding of:
A. Peptide-MHC complexes on the APC to the TCR on the T cell
B. CD4 on the T cell to nonpolymorphic regions of class II MHC molecules on the
APC
C. Integrins on the T cell with adhesion ligands on the APC
D. B7-2 on the APC with CD28 on the T cell
E. CD40L on the T cell with CD40 on the APC

ANS: E. CD40L is not expressed on naive T cells and is only up-regulated subsequent to
activation by an antigen-presenting cell (APC). In the naive helper T cell, the TCR binds
to the MHC-peptide complex whereas the CD4 coreceptor engages a conserved region on
the MHC II molecule. Integrins on the T cell interact with adhesion ligands on the APC.
This region of binding between the T cell and the APC is known as the immunologic
synapse and also includes costimulatory interactions, such as CD28 on the T cell binding
to B7 on the APC.
2. Which one of the following statements about MHC-TCR interactions is NOT true?
A. Antigen receptors on T cells bind to MHC molecules for only brief periods of
time.
B. The affinity of most TCRs for peptide-MHC complexes is similar to the affinity
of antibodies for their antigens.
C. Only 1% or less of the MHC molecules on any antigen-presenting cell (APC)
display a peptide recognized by a particular T cell.
D. T cells usually require multiple engagements with an APC before a threshold of
activation is reached.
E. A subthreshold number of MHC-TCR interactions can lead to T cell inactivation.

ANS: B. In general, the TCR binds to peptide-MHC complexes with lower affinity than
antigen-antibody interactions. This relatively low-affinity interaction occurs briefly; thus,
a T cell may need multiple engagements with the antigen-presenting cell (APC) before a
threshold of activation occurs. If this threshold is not reached, the T cell may enter into an
inactive state known as anergy. On any given APC, less than 1% of the MHC molecules
display the same peptide.




Matching

,Questions 3-10
For each of the descriptions in questions 3-10, choose the T cell signaling molecule that
best matches it from the list below (A-O).
A. CD3
B. Lck
C. Zap-70
D. LAT
E. Ras
F. PLC
G. PIP2
H. PIP3
I. IP3
J. DAG
K. Calcineurin
L. NFAT
M. Jun
N. Fos
O. NF-B

3. This molecule becomes an active transcription factor on dephosphorylation.

ANS: L. NFAT is a transcription factor required by T cells for the expression of
interleukin (IL)-2, IL-4, tumor necrosis factor (TNF), and other cytokine genes. NFAT is
present in an inactive, phospN hoUryRlS
ateIdNG rmB.
foT inCO
thM
e cytosol of resting T cells. On
dephosphorylation by calcineurin, a nuclear localization sequence is uncovered that
permits NFAT to translocate to the nucleus. Once in the nucleus, NFAT induces
transcription of these genes.

4. This protein is a well-characterized proto-oncogene product that on mutation to a
constitutively active form has been associated with multiple neoplasms.

ANS: E. Ras was one of the first proto-oncogenes characterized. Normal ras is involved
in TCR signaling pathways. On mutation to a constitutively active state, ras promotes the
survival and proliferation of malignant cells.

5. Binding of this molecule to Jun is needed for transcriptional activation of the IL-2
gene.

ANS: N. Fos combines with phosphorylated Jun to form activation protein-1 (AP-1). AP-
1 is the name for a family of DNA-binding factors composed of dimers of two different
proteins. Transcription of fos is enhanced by the Erk pathway, whereas phosphorylation
of preexisting Jun is induced through the Vav/Rac pathway. AP-1 physically associates
with other transcription factors in the nucleus, and together they activate transcription of
cytokine genes essential for T cell activation.

6. This is a transcription factor that exists in the phosphorylated form within the nucleus.

,Test Bank 3


ANS: M. On phosphorylation, c-Jun translocates to the nucleus and binds to Fos to form
AP-1.

7. Immunosuppressive therapy with the drugs cyclosporine and FK506 inhibits T cell
activation by blocking the protein phosphatase activity of this molecule.

ANS: K. Calcineurin is responsible for the dephosphorylation of NFAT, which is an
essential transcription factor for the activation of T and B cells. The immunosuppressive
drugs cyclosporine and FK506 function by inhibiting calcineurin. These drugs are
commonly used to prevent transplant rejection.

8. This molecule binds to a receptor on the endoplasmic reticulum and stimulates release
of calcium into the cytosol.

ANS: I. IP3 is generated from the cleavage of PIP2 in the membrane to DAG and IP3 by
the enzyme PLC, and it stimulates release of calcium into the cytosol.

9. This molecule has the same downstream effect as addition of the drug phorbol
myristate acetate (PMA) to T cells.

ANS: J. Both DAG and pharmacologic agents such as phorbol myristate acetate (PMA)
activate protein kinase C (PKC). PKC has many substrates and is a potent activator of
many transcription factors in T cells.

10. This molecule is a transcriN ioR
ptU nSfaI orGiT
ctN nvBo.
lvC
edOM
in the expression of several T cell
activation genes activated when its bound inhibitor is phosphorylated.

ANS: O. NF-B is present in the cytoplasm and is bound to an inhibitor called I-B. On
stimulation with antigen, I-B becomes phosphorylated, dissociates from NF-B, and is
degraded by the ubiquitin-proteosomal pathway. NF-B then translocates to the nucleus,
where it participates in transcriptional activation of several genes.

, Abbas: Cellular and Molecular Immunology, 8th Edition
Antibodies and Antigens

Test Bank

Matching

Questions 1-5
Match each of the descriptions in questions 1-5 with the correct lettered antibody isotype
(A-E). (Answers may be used more than once.)
A. IgA
B. IgD
C. IgE
D. IgG
E. IgM

1. The secreted form of this isotype forms pentamers around a J chain

ANS: E. IgM is secreted as a J chain–linked pentamer.

2. The most abundant Ig isotype in the blood
ANS: D. The blood IgG concentration is about 3.5 mg/mL and includes four subtypes
(IgG1 to IgG4).
3. The isotype only found in membrane-bound form on naive B cells

ANS: B. IgD is not secreted and is found only on the surface of naive B cells. Its function
is not well understood.

4. The isotype found predominantly in mucosal secretions
ANS: A. IgA accounts for almost two thirds of the 3 g of antibody produced each day by
an adult, most of which is produced in the gastrointestinal mucosa.

5. The isotype most closely associated with immediate hypersensitivity (allergic)
disease

ANS: C. Most IgE that is secreted is bound to mast cells, and it plays a role in the
activation of mast cells during allergic reactions.

Questions 6-10

Match each description in questions 6-10 with the appropriate lettered term (A-I).
A. Conformational determinant
B. Linear determinant
C. Neoantigenic determinant
D. Hinge region

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