C-reactive protein is a
A) pathogen-associated molecular pattern (PAMP).
B) homotrimeric adaptor protein.
C) lipoprotein.
D) pattern recognition
... [Show More] receptor (PRR).
2) Pattern recognition receptors (PRRs) are found on which of the following cells?
A) macrophages
B) bacteria
C) neutrophils
D) macrophages and neutrophils
3) Which of the following biomolecules interact with toll-like receptors (TLRs)?
A) bacterial LPS
B) immunoglobulins
C) major histocompatibility complex proteins
D) none of these
4) Interaction of a pathogen-associated molecular pattern (PAMP) with a pattern recognition receptor (PRR) results in
A) formation of transmembrane pores that cause cell lysis.
B) transmembrane signal transduction that initiates transcription of genes involved in phagocytosis, inflammation, and pathogen killing.
C) molecular activation of the adaptive immune system.
D) a superantigen reaction that can cause septic shock.
5) Which of the following are proteins that interact directly with antigens during the adaptive immune response?
A) immunoglobins
B) major histocompatibility complex
C) T cell receptors
D) all of these
6) The C domain of antigen-binding proteins functions to
A) attach the antigen-binding domain to the cytoplasmic membrane.
B) bind to the cytoplasmic membrane of foreign cells.
C) complex multiple antigen-binding proteins together.
D) bind to epitopes.
7) The main bonds present in the C domain of antigen-binding proteins are
A) hydrogen bonds.
B) intrachain disulfide bonds.
C) ionic bonds.
D) van der Waals forces.
8) TCRs associate with the adapter molecule
A) CD3.
B) CD28.
C) Igα.
D) Igβ.
9) Class II MHC proteins have grooves with
A) closed ends.
B) open ends.
C) both open and closed ends.
D) neither open nor closed ends.
10) Which of the following is/are MHC class I genes?
A) HLA-A
B) HLA-B
C) HLA-C
D) HLA-A, HLA-B, and HLA-C
11) An individual usually expresses ________ structurally distinct allele(s) that encode class I MHC proteins.
A) one
B) two
C) four
D) six
12) Antibodies consist of four polypeptides, ________ heavy chains, and ________ light chains.
A) one / three
B) two / two
C) three / one
D) four / four
13) Each of the V domains in immunoglobulins has ________ complementarity-determining regions.
A) one
B) two
C) three
D) four
14) An epitope is ________ amino acids long.
A) 3-5
B) 10-15
C) 50-60
D) 700
15) Clonal anergy is a state of
A) antibody production.
B) high energy.
C) unresponsiveness.
D) high energy and antibody production.
16) Which of the following contribute to the limitless diversity generated from a relatively fixed number of immunoglobulin genes?
A) hypermutation
B) random heavy and light chain reassortment
C) somatic recombination
D) hypermutation, random heavy and light chain reassortment, and somatic recombination.
17) Assuming that each heavy and light chain has an equal chance to be expressed in each cell, approximately how many possible antibodies can be expressed?
A) 192
B) 1,920
C) 19,200
D) 1,920,000
18) Somatic hypermutation occurs only in the ________ regions of rearranged heavy and light chains.
A) D
B) HV
C) J
D) V
19) The two-stage thymic selection process for selecting self-tolerant, antigen-reactive T cells results in
A) allelic exclusion.
B) clonal deletion.
C) complementarity-determining regions.
D) somatic hypermutation.
20) More than ________ % of all T cell precursors that enter the thymus do NOT survive the selection process.
A) 15
B) 25
C) 45
D) 95
21) Which of the following is involved in B cell selection and tolerance?
A) clonal anergy
B) clonal deletion
C) clonal anergy and deletion
D) allelic exclusion
22) Which of the following roles do B cells play?
A) antigen presentation
B) antigen processing
C) antigen uptake
D) antigen presentation, processing, and uptake
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23) The complete second signal for B cell activation requires which of the following interactions?
A) CD40-CK40L interaction
B) cytokine-cytokine receptor interaction
C) TH-B cell interaction
D) All of these are necessary.
24) Communication between cells of the immune system is accomplished in many cases through
A) allelic exclusion.
B) clonal deletion.
C) cytokines.
D) allelic exclusion, clonal deletion, and cytokines.
25) Chemokines are a group of small proteins that
A) attract T cells to sites of injury.
B) function as chemoattractants for phagocytes and lymphocytes.
C) potentiate specific immune responses.
D) attract T cells, phagocytes, and lymphocytes, as well as potentiate specific immune responses.
26) Which of the following are soluble mediators and activators for T lymphocytes and B cells?
A) IL-2
B) IL-4
C) IL-5
D) IL-2, IL-4, and IL-5
27) Which of the following stimulate macrophage differentiation and activation?
A) granulocyte-monocyte colony stimulating factor
B) interferon gamma
C) tumor necrosis factor-alpha
D) granulocyte-monocyte colony stimulating factor, interferon gamma, and tumor necrosis factor-alpha
28) Which of the following cytokines acts to stimulate natural killer cells and induce naïve T cells to differentiate to TH1 cells?
A) IL-1β
B) IL-6
C) IL-12
D) TNF-α
29) Chemokines produced by activated macrophages include
A) CXL8.
B) CCL2.
C) MCP-1.
D) CXL8, CCL2, and MCP-1.
30) The chemokine CCL2
A) attracts basophils, eosinophils, monocytes, and dendritic cells.
B) stimulates production of inflammatory mediators.
C) organizes an antigen specific immune response.
D) attracts basophils, eosinophils, monocytes, and dendritic cells; stimulates production of inflammatory mediators; and organizes an antigen specific immune response.
31) The PAMP recognized by mannose-binding lectin (MBL) is the sugar mannose, found as a repeating subunit in
A) human mucus.
B) lymphocyte receptors.
C) bacterial and fungal polysaccharides.
D) bacterial peptidoglycan.
32) Which of the following is a likely target for a toll-like receptor (TLR)?
A) tumor necrosis factor
B) interleukin IV
C) flagellin
D) insulin
33) Interaction of a PAMP with a TLR triggers transmembrane signal transduction and subsequent
A) clonal expansion.
B) antibody production.
C) complement protein activation.
D) phagocytosis and inflammation.
34) Signal transduction pathways initiate activation of transcription after specific
A) TH cell death.
B) ligand-receptor binding on the cell surface.
C) cytokines diffuse across the cytoplasmic membrane.
D) antigen-antibody binding.
35) The ________ is a highly conserved amino acid sequence found in immunoglobulin, TCR, and MHC proteins.
A) heavy chain
B) V domain
C) C domain
D) light chain
36) Immunoglobulins and TCRs associate with adaptor molecules that have
A) a C domain.
B) immune-based tyrosine-activation motifs (ITAMs).
C) pathogen recognition receptors.
D) toll-like receptors.
37) The major histocompatibility complex is also called the
A) human leukocyte antigen (HLA).
B) T cell receptor.
C) toll-like receptor complex.
D) T cell receptor or toll-like receptor.
38) The ________ and ________ domains of the class II MHC protein interact to form a peptide-binding site.
A) B / T
B) light / heavy
C) C / V
D) α1 / β1
39) The occurrence of multiple alleles at a specific locus is called
A) signal transduction.
B) the variable domain.
C) polymorphism.
D) allelic exclusion.
40) The peptides bound by a single MHC protein share a common
A) C domain.
B) peptide motif.
C) V domain.
D) nucleotide sequence.
41) The invariant amino acids in each peptide motif bound by MHC proteins are called
A) anchor residues.
B) MHC peptides.
C) antigen-binding immunoglobulins.
D) TCR peptides.
42) Amino acid variability is especially apparent in several ________ in the V domains of different immunoglobulins.
A) heavy chains
B) complementarity-determining regions (CDR)
C) peptide motifs
D) epitopes
43) The antigen-binding site of an antibody accommodates a small portion of the antigen called a(n)
A) lipopolysaccharide.
B) epitope.
C) peptide motif.
D) pathogen associated molecular pattern (PAMP).
44) ________ ensures that each B cell produces only one immunoglobulin.
A) Self-activation
B) Allelic exclusion
C) MHC interaction
D) Clonal deletion
45) The mechanism by which antigen-reactive cells respond to foreign antigens while ignoring self-antigens is called clonal
A) selection.
B) deletion.
C) anergy.
D) expansion.
46) The failure to develop tolerance may result in dangerous reactions to self-antigens, a condition called
A) type I hypersensitivity.
B) immunotolerance.
C) autoimmunity.
D) immunodeficiency.
47) In B cell selection and tolerance, if no signal is generated from ________ cells, the B cells remain unresponsive.
A) TC
B) TH
C) B7
D) CD28
48) Some activated B cells are transformed into ________ cells that secrete antibodies, and others remain as ________ cells.
A) plasma / memory B
B) lymphocytes / memory B
C) immunoglobulin / plasma
D) immunoglobulin / TH
49) Cytokines produced by lymphocytes are often called
A) interleukins.
B) pathogen recognition receptors.
C) chemokines.
D) epitopes.
50) All proinflammatory cytokines EXCEPT ________ induce fever at the systemic level.
A) IL-4
B) IL-12
C) IL-6
D) IL-17
51) When two allelic variants are expressed equally, they are said to be
A) exclusive.
B) uncommitted.
C) repressed.
D) codominant.
True/False Questions
1) Mannose on mammalian cells is inaccessible to mannose-binding lectin.
2) All TLR can react with only one specific PAMP.
3) TCRs are found exclusively on T cells.
4) Immunoglobulin, TCR, and MHC proteins share structural features and have evolved by duplication and selection of primordial antigen receptors.
5) B cells react with antigens through TCR antigen receptors.
6) Antigen receptors can directly connect to signal transduction pathways because immunoglobulins and TCRs have very small cytoplasmic domains.
7) The cytoplasmic domains of immunoglobulins and TCRs have cytoplasmic tyrosines that can be phosphorylated.
8) Immunoglobins associate with the adapter molecules Igα and Igβ.
9) Adapter molecules associate covalently with their respective antigen receptors in the membrane.
10) The human leukocyte antigen spans about 4Mbp on human chromosome 6.
11) The embedded peptides in MHC proteins are normally derived from breakdown products of cell metabolism.
12) The arrangement of Class II MHC proteins in pairs or trimers enhances their stability.
13) Class I MHC proteins have grooves with open ends.
14) Each immunoglobulin or TCR interacts with a single antigen, but MHC proteins can interact with more than one antigen.
15) Antibodies are insoluble proteins.
16) In somatic hypermutation, the mutation of immunoglobulin genes occurs at much higher rates than the mutation rates observed in other genes.
17) Affinity maturation is one of the factors responsible for a stronger secondary immune response.
18) In antigen binding, MHC protein binds to the T cell epitope, whereas the TCR binds the MHC motif.
19) Somatic hypermutation mechanisms generate TCR diversity.
20) The clonal selection theory states that each antigen-reactive B cell or T cell has a cell surface receptor for a single antigen epitope.
21) In clonal selection, cells that have not interacted with antigen do not proliferate.
22) Selection against self-reactive clones results in the development of tolerance.
23) T cells undergo immune selection FOR potential antigen-reactive cells and selection AGAINST those cells that react strongly with self-antigens.
24) Some immature B cells are reactive to self-antigens but do not become activated even when exposed to high concentrations of self-antigens.
25) After a B cell is activated, it no longer needs T cell interactions or cytokines to make antibody.
Essay Questions
1) Describe the signal transduction pathway that is activated when LPS binds to TLR-4.
2) What role does the C domain play in cell surface proteins that interact directly with antigens?
3) What is the effect of an antigen binding a membrane protein on adapter molecules?
4) A patient is waiting for a kidney transplant. In order for the transplant to be successful, the donated kidney (the graft) must "match" with the recipient. What has to "match" between the donor and the recipient? Why is matching tissue more difficult than matching blood types?
5) Major histocompatibility complex (MHC) proteins, antibodies, and T cell receptors are all highly variable so that they can interact with a large number of different antigens. How is variability generated for each of these important antigen-binding proteins?
6) Predict the consequence for an individual of a deleterious genetic mutation in the gene for TLR-4.
7) Design five amino acid peptides that could be bound by a single hypothetical class I MHC protein. The MHC proteins binds peptides that are 10 amino acids long and have two anchor residues, tyrosine and isoleucine, at positions 2 and 5.
8) Why is the secondary immune response stronger in regard to antibodies?
9) Given that T cell receptors (TCRs) are randomly generated during the maturation process, how are new T cells selected that can recognize self-antigens and other immune cells appropriately? [Show Less]