Immunology Test TwoDiacylglycerol (DAG) is one of the two products generated when PLC- cleaves the membrane phospholipid, PIP2. This small lipid mediator remains associated with the plasma membrane and induce calcium entry into the cell. You Answered

Diacylglycerol (DAG) is one of the two products generated when PLC-y cleaves the membrane phospholipid, PIP2. This small lipid mediator remains associated with the plasma membrane and induce calcium entry into the cell.

True
False

False

Which of the following alterations would result in increased signaling activity of Ras?

A) mutation in Ras that renders it unsusceptible to the activities of GEFs
B) Overexpression of GEFs
C) Depletion of GTP in the cytoplasm
D) A mutation in Ras that enhances its GTPase activity
E) Overexpression of GAPs

B) Overexpression of GEF's

When T cells express defective ER calcium sensor protein, they secret very little IL-2 because activation of one of the following transcription factors is compromised. That transcription factor is:

A) NFAT
B) NF-kappaB
C) IRF3
D) AP-1

A) NFAT

Integrin-dependent T cell adhesion to antigen-presenting cells increases substantially following TCR stimulation. This increased integrin-dependent adhesion is mediated in part by:

A) Increased transport of intracellular pools of LFA-1 to the cell surface
B) Increased phosphorylation of the LFA-1 cytoplasmic tail
C) LFA-1 conversion to a high affinity binding state
D) Activation of Cdc42 and WASp
E) Increased synthesis of the LFA-1 protein

C) LFA-1 conversion to a high affinity binding state

Like TCR signaling, B cell receptor (BCR) signaling is initiated by a kinase phosphorylating tyrosine resides in ITAM motifs of BCR signaling subunits.

True
False

True

Lymphocyte activation leads to robust proliferation and effector cell differentiation. The metabolic demands of these processes are met, in part, by up-regulation of glycolytic enzymes and nutrient transporters on the activated cell membrane. A key intermediate in the signaling pathway leading to enhanced glucose metabolism following antigen receptor stimulation is:

A) Increase in cytoplasmic Ca2+
B) Cleavage of the membrane phospholipid, PIP2
C) The phosphoinositide, PIP3
D) The lipid mediator diacylglycerol (DAG)
E) The mitochondrial protein, Bcl-2

C) The phosphoinositide, PIP3

Which of the following statements is the best example of a primary lymphoid organ?

A) Peyer's patch
B) Spleen
C) Lymph nodes
D) Thymus

D) Thymus

Direct V-J rearrangement occurs during which phase of a B cell's development?

A) Pro-B cell
B) Activated B cell
C) Answer Pre-B cell
D) Mature B cell
E) Immature B cell

C) Answer Pre-B cell

During B cell development, pre-B-cell receptors receive signals from self-antigens for the lymphocytes to survive and proliferate.

True
False

False

In negative selection, B cells that interact strongly with self-antigens may be rescued by receptor editing. During receptor editing, both heavy chain and light chain loci go through successive rearrangement events until the B cell produce a new B cell receptor that is not self reactive.

True
False

False

Where do immature B cells finish their maturation?

A) Bone marrow
B) Liver
C) Spleen
D) Thymus
E) Mucosal-associated lymphoid tissues

C) Spleen

An individual with normal B cells, but an absence of T cells might have a defect in:

A) Thymic stromal cells
B) RAG-1 or RAG-2 recombinase proteins
C) Hematopoietic stem cells
D) Bone marrow stromal cells
E) Terminal deoxynucleotidyl transferase (TdT)

A) Thymic stromal cells

In mice that lack both MHC class I and class II in the thymus, T cell development will show:

A) A block in T cell development at the CD4-CD8- double-negative stage
B) A 100-fold decrease in total thymocytes numbers
C) Normal numbers and subsets of thymocytes and peripheral T cells
D) A block in T cell development at the CD4+CD8+ double-positive stage
E) Normal numbers of thymocytes, but no peripheral T cells

D) A block in T cell development at the CD4+CD8+ double-positive stage

Which of the following options correctly describes a difference between the B-cell receptor and the T-cell receptor?

A) TCRα chains cannot undergo successive rearrangements, as opposed to B-cell receptors, which go through the process of receptor editing.
B) T cells do not require the formation of a pre-T-cell receptor in order to advance their development, as opposed to B cells, which require signaling through the pre-B-cell receptor in order to undergo allelic exclusion and continue development.
C) VDJ rearrangement of the T-cell receptor β chain occurs first in T-cell development, as opposed to the B-cell receptor, which undergoes VDJ rearrangement after light chain VJ rearrangement.
D) Expression of the B-cell receptor stops further light chain rearrangement and enforces strict allelic exclusion, while expression of the T-cell receptor does not restrict further rearrangements of the alpha chain until there is

D) Expression of the B-cell receptor stops further light chain rearrangement and enforces strict allelic exclusion, while expression of the T-cell receptor does not restrict further rearrangements of the alpha chain until there is signaling through peptide:MHC binding, resulting in many T cells that express two different TCRα chains.

T cell development in the thymus shares some similarities to a pipeline. As new progenitor cells enter the thymus, the most mature thymocytes are passively pushed out of the thymus to enter the circulation.

True
False

False

Self-reactive B cells can be eliminated from the repertoire at several stages of B cell maturation, including immature B cells that have already emigrated from the bone marrow into the circulation. This latter stage of tolerance induction is critical because:

A) Receptor editing is not a perfect process and some self-reactive B cells may fail to be eliminated in the bone marrow.
Immature B cells are trapped in the bone marrow by strong B-cell receptor cross-linking.
B) You Answered Circulating immature B cells do not encounter tissue-specific antigens in peripheral organs and tissues.
C) Immature circulating B cells are more sensitive to antigen stimulation than the developing B cells in the bone marrow.
D) Not all self-antigens are expressed or present in the bone marrow during B cell development.

D) Not all self-antigens are expressed or present in the bone marrow during B cell development.

What are the specialized cell type involved in the entry of lymphocytes into lymph nodes called?

A) High endothelial venules (HEV) cells
B) Dendritic cells (DCs)
C) Stromal cells
D) Follicular helper T cells (TFHs)
E) Macrophages

A) High endothelial venules (HEV) cells

When an activated conventional dendritic cell (cDC) arrives at the nearby lymph node, it has _____ phagocytic activity and _____ expression of MHC and costimulatory molecules.

A) low; low
B) low; high
C) high; high
D) high; low

B) low; high

What of the following functions cannot be carried out by macrophages?

A) Phagocytosis
B) Antigen processing
C) Antigen presentation to activated T cells
D) Activation of naive T cells

D) Activation of naive T cells

When a naïve T cell recognizes peptide:MHC complex on an APC, the T cell shows activation responses, including the up-regulation of multiple genes. For the T cell to undergo robust proliferation, which of the following signals are required?

A) Antibodies
B) Pathogen-associated molecular patterns (PAMPs)
C) The adhesion molecule ICAM1
D) B7 family ligands
E) Anti-inflammatory cytokines

D) B7 family ligands

Unlike innate immune responses, adaptive immune responses are initiated in secondary lymphoid organs. However, the innate immune response to an infection in a tissue has a pivotal role in inducing T-cell responses in the nearest lymph node by activating tissue dendritic cells and inducing their migration to the lymph node.

True
False

True

Naive T cells scan the dendritic cells in the cortical region of the lymph node as they migrate. The initial encounter of T cells with dendritic cells is mediated by interactions between the T-cell receptor and the peptide:MHC complexes on the dendritic cell.

True
False

False

Cytotoxic T cells that lack expression of perforin are more defective in killing target cells than those that lack granzymes.

True
False

True

Which cytokine is produced by TH1 cells?

A) IL-17
B) IL-4
C) TGF-β
D) IFN-γ
E) IL-1

D) IFN-γ

In the majority of viral infections, CD8 T-cell activation requires CD4 T-cell help

True
False

True

Which of the following is a common consequence of TCR and CCR7 signaling?

A) Negative selection
B) Differentiation into TH1 cells
C) Positive selection
D) Differentiation into Treg cells
E) LFA-1 transition to a high-affinity form

E) LFA-1 transition to a high-affinity form