Cumulative Questions Flashcards
Which of the following generally does not apply to bone marrow (a primary lymphoid organ)
but does apply to secondary lymphoid organs?
Antigen-dependent response
Which of the following is involved in recognition of intracellular pathogens in innate immune
cells?
NOD-like receptors (NLRs)
Which of the following is a correct statement about NK cells?
They kill target cells in an extracellular fashion
Mature dendritic cells are capable of which of the following?
Activating naïve antigen-specific T cells
Killer-cell inhibitory receptors (KIRs) expressed by NK cells bind to which of the following to
prevent killing of normal cells:
MHC class I
Which of the following applies uniquely with respect to B cells found in secondary lymphoid
organs?
Terminally differentiate into plasma cells
The germinal centers found in the cortical region of lymph nodes and the peripheral region of
splenic peri- arteriolar lymphatic tissue
Provide an infrastructure that on antigenic stimulation contains large populations of B
lymphocytes and plasma cells
Which of the following sequence correctly describes lymphocyte migration from lymph nodes to
blood?
Postcapillary venules, efferent lymphatic vessels, thoracic duct, vena cava, heart
Clonal expansion of which of the following cells occurs following their direct interaction with the
antigen for which they are specific?
B cells
A large glycoprotein has been enzymatically digested in the laboratory to yield a mixture of
glycopeptides ranging in size from 4 to 6 amino acids in length. Which of the following would
be expected if the peptide mixture were administered to an experimental animal together with
an adjuvant such as complete Freund’s adjuvant?
There would be neither a humoral nor cell-mediated immune response to the peptides in
the mixture
The protection against smallpox virus infection afforded by prior infection with cowpox virus
represents
Antigenic cross-reactivity
Converting a toxin to a toxoid
Reduces the pharmacological activity of the toxin
Haptens
A) require carrier molecules to be immunogenic, B) react with specific
antibodies when homologous carriers are not employed C) interact with specific
antibody even if the hapten is monovalent D) cannot stimulate secondary
antibody responses without carriers
An adjuvant is a substance that
Enhances the immune response to the immunogen
A polyclonal antibody made against a large protein antigen reacts with it even when it is
denatured by disrupting all disulfide bonds. Another monoclonal antibody against the antigen
fails to react when it is similarly denatured. The most likely explanation can be stated as follows:
The polyclonal antibody contains antibodies specific for several non-conformational
epitopes expressed by the antigen
Functional properties of immunoglobulins such as binding to Fc receptors are associated with
Heavy chains
The idiotype of an antibody molecule is determined by the amino acid sequence of the
Variable regions of the heavy and light chains
Which of the following would generate a polyclonal rabbit antiserum specific for human γ
heavy-chain, κ chain, λ chain, and Fc regions of Ig:
Pooled IgG
A polyclonal antiserum raised against pooled human IgA will react with
A) human IgM, B) κ light chains, C) human IgG, D) J chain
An individual was found to be heterozygous for IgG1 allotypes 3 and 12. The different possible
IgG1 antibodies produced by this individual will never have
Two heavy chains, one of allotype 3 and one of allotype 12
Papain digestion of an IgG preparation of antibody specific for the antigen hen egg albumin
(HEA) will
Produce two Fab molecules and one Fc fragment
If an individual who is highly allergic to cat dander is exposed to a pet cat in a friend’s house,
which class of immunoglobulin would most likely be found to be elevated soon after this
exposure?
IgE
Which of the following immunoglobulins can activate complement as a single molecule when
bound to an antigen?
IgM
The relative level of pathogen-specific IgM antibodies can be of diagnostic significance because
Relatively high levels of IgM often correlate with a first and recent exposure to the
inducing agent
Primary and secondary antibody responses differ in
A) the predominant isotype generated, B) the number of lymphocytes
responding to antigen, C) the time it takes for measurable amounts of
antibodies to appear in the serum, D) the biologic functions manifested by the
Ig isotypes produced
In an individual predisposed to allergic responses, which of the following statement best
describes the outcome of his/her exposure to an allergen:
Clinical reactions such as wheezing and sneezing may soon manifest soon after exposure
due to the presence of allergen-specific IgE that is retained by cells such as mast cells that
express Fcε receptors
Which of the following is required to ensure the integrity and stability of immunoglobulin
molecules but is not associated with interactions between antigens and antibodies?
Covalent bonds
If an IgG antibody preparation specific for hen egg lysosome (HEL) is treated with papain to
generate Fab fragments, which of the following statements concerning the avidity of such
fragments is true?
They will have a lower avidity for HEL as compared with the intact IgG
Western blot assays used to test serum samples for the presence of antibodies to infectious
agents, such as HIV, are particularly useful as diagnostic assays because
Antibodies specific for multiple antigenic epitopes can be detected
The major difference between transgenic mice and knockout mice is that
Transgenic mice have a functional foreign gene added to their genome
SCID mice have a genetic defect that prevents development of functional
B cells and T cells
Which of the following statements regarding B cell hybridomas is true?
They are derived by fusing B Cells with malignant plasma cells that are unable to secrete
immunoglobulin
An ELISA designed to test for the presence of serum antibody for a new strain of pathogenic
bacteria is under development. Initially, a monoclonal antibody specific for a single epitope of
the organism was used both to sensitize the wells of the ELISA plate and as the enzyme- labeled
detecting antibody in a conventional sandwich ELISA. The ELISA failed to detect the antigen
despite the use of a wide range of antibody concentrations. What is the most probable cause of
this problem?
The monoclonal antibody used to sensitize the wells is blocking access of the epitope;
thus, when the same antibody is enzyme-labeled, it cannot bind to the antigen
The DNA for an H chain in a B-cell making IgG2 anti- body for diphtheria toxoid has the
following structure: 5′-V17D5J2 Cγ2–Cγ4–Cε–Cα2–3′. How many individual rearrangements
were required to go from the embryonic DNA to this B-cell DNA?
3
If you had 40V, 25D, and 6J regions able to code for an H chain and 40V and 5J-region genes
able to code for an L chain, you could have a maximum repertoire of:
More than 1,200,000 specificities
The antigen specificity of a particular B cell:
Is determined by H+L-chain variable-region sequences
If you could analyze at the molecular level a plasma cell making IgA antibody, you would find all
of the following except:
mRNA specific for μ chains
The ability of a single B cell to express both IgM and IgD molecules on its surface at the same
time is made possible by:
Alternative RNA splicing
Which of the following statements concerning the organization of Ig genes is correct?
The VDJ segments coding for an Ig VH region may associate with different H-chain
constant-region genes
Which of the following does not contribute to the antigen-binding site diversity of B-cell antigen
receptors?
Inheritance of multiple C-region genes
Which of the following statements regarding a B cell expressing both IgM and IgD on its
membrane is incorrect?
The IgM and IgD have different antigenic specificities
Which of the following plays a role in changing the antigen binding site of a B cell after
antigenic stimulation?
Somatic hypermutation
The earliest stages of B-cell differentiation:
Involve rearrangement of heavy-chain gene segments
Which of the following is expressed on the surface of the mature B lymphocyte?
A) CD40, B) MHC class II molecules, C) CD32, D) IgM and IgD
Which of the following statements is incorrect?
Synthesis of antibody in a primary response to a thymus-dependent antigen occurs
predominantly in the blood
Immature B lymphocytes:
Are at a stage of development where contact with antigen may lead to receptor editing
and deletion
Antigen binding to the B-cell receptor:
Transduces a signal through the Igα and Igβ molecules
Which of the following would not be found on a memory B cell?
Surrogate light chains
Germinal centers found in lymph nodes and spleen:
Are sites where antigen-activated mature B cells proliferate and differentiate
All the following are characteristics of both MHC class I and II molecules except:
They are expressed constitutively on all nucleated cells
MHC class I molecules are important for which of the following?
Binding to CD8 molecules on T cells
Which of the following is incorrect concerning MHC class II molecules?
MHC class II molecules are associated with β2-microglobulin on the cell surface.
The peptide transporter TAP
Transports peptides into the endoplasmic reticulum for binding to MHC class I
Which of the following statements about HLA genes is incorrect?
They code for both chains of every HLA class I molecule expressed.
Which of the following is found on the surface of every B cell, T cell, and pancreatic cell?
MHC class I molecules
After a virus infects a boy’s liver cells, which of the following about the processing and
presentation of virus- derived proteins is correct?
Some virus-derived peptides are presented to CD8+ T cells.
Which of the following statements concerning T-cell development is correct?
Interaction with thymic nonlymphoid cells is critical.
The development of self-tolerance in the T-cell compartment is important for the prevention of
autoimmunity. Which of the following results in T-cell self-tolerance?
negative selection
Which of the following statements is correct?
CD4+ CD8+ T cells form the majority of T cells in the thymus.
Which of the following is incorrect regarding mature T cells that use αβ as their antigen-specific
receptor?
They can further rearrange their TCR genes to express γδ as their receptor.
Which of the following statements is incorrect concerning TCR and Ig genes?
Both Ig and TCR are able to switch C-region usage.
Which of the following statements is incorrect concerning antigen-specific receptors on both B
and T cells?
They have extensive cytoplasmic domains that interact with intracellular molecules
Which of the following is correct concerning the characteristics of T cells that exit the thymus?
They express either CD4 or CD8 with a TCR that has low to moderate affinity for MHC
plus self-antigen.
The role of the APC in the immune response is all of the following except:
To present nonself-peptides associated with MHC class I molecules to CD4+ T cells
Which of the following statements about IL-2 is incorrect?
It is produced primarily by activated macrophages.
Which of the following pairs of cell surface proteins do NOT interact with each other?
Membrane Ig on the B cell and CD4 on the T cell
Which of the following statements about the activation of CD4+ T cells is incorrect?
The interaction between peptide–MHC class II on an APC and the TCR of an appropriate CD4+ T cell is necessary and sufficient for full T-cell activation.
Which of the following statements about cytokines and subsets of CD4+ T cells is incorrect?
Cytokines synthesized by TH1 and TH2 cells inhibit the action of Treg cells.
Which of the following statements about CD8+ CTL is incorrect?
They cannot kill CD4+ T cells.
Infection with vaccinia virus results in the priming of virus-specific CD8+ T cells. If these vaccinia
virus- specific CD8+ T cells are subsequently removed from the individual, which of the
following cells will they kill in vitro?
Vaccinia-infected cells expressing the same MHC class I molecules as the individual
Polarization of naïve CD4+ T-cell differentiation toward the TH2 lineage is associated with which
of the following cytokines?
IL-4
A patient with active rheumatoid arthritis feels systemically ill with low-grade fever, malaise,
morning stiffness, and fatigue. The protein(s) or cytokine(s) most likely to be responsible for
these symptoms are:
TNF and IL-1
When IL-2 is secreted by antigen-specific T cells activated due to presentation of antigen by
APCs, what happens to naïve antigen-nonspecific T cells in the vicinity?
Nothing happens
IL-1, IL-6, and TNF-α are proinflammatory cytokines that are known to
A) cause increased vascular permeability, B) act in concert with chemokines to
promote migration of inflammatory cells to sites of infection, C) initiate acutephase
responses, D) have endogenous pyrogen properties
Which of the following cytokines plays a role in terminating inflammatory responses?
TGF-β
Assuming there were no other compensatory mechanisms to replace IL-8 function, which of the
following would be preserved as a functional activity in an IL-8 knockout mouse strain?
Reduction of cytokine production by TH1 cells
Superantigens cause a burst of cytokine production by T cells due to their ability to
Cross-link the Vβ segments of T-cell receptors with class II MHC molecules on APCs
An individual normally does not make an immune response to a self-protein because:
Lymphocytes that express a receptor reactive to a self-protein are inactivated by
deletion, anergy, or receptor editing.
Which of the following autoimmune diseases has been proven to be due to a single gene
defect?
Autoimmune lymphoproliferative syndrome (ALPS)
Rheumatoid factor, found in synovial fluid of patients with rheumatoid arthritis, is most
frequently found to be:
IgM reacting with H-chain determinants of IgG
In which of the following diseases do TH1 CD4+ cells, cytotoxic CD8+ T cells, and autoantibody
all contribute to the pathology?
type I diabetes mellitus
A 22-year-old woman has an erythematous rash on the malar eminences of her face that gets
worse when she goes out in the sun. She has lost about 10 pounds, com- plains of generalized
joint pain, and feels tired much of the time. Physical examination is normal except for the rash.
Laboratory tests reveal a WBC count of 5500 (normal). Urinalysis shows elevated levels of
protein in
high levels of antibodies to double-stranded DNA
Blocking any of the following processes can result in peripheral tolerance in mature T cells
except:
negative selection of thymocytes
Which of the following is least likely to lead to autoimmunity?
increased clearance of immune complexes
A 30-year-old woman with a previous history of rheumatic fever has recently developed a heart
murmur. The most likely cause is:
molecular mimicry of a streptococcal antigen and cardiac myosin
Curtis Jones, a retired sanitation worker, developed double vision. Upon neurologic
examination he was observed to have weakness of his facial muscles and his tongue and
abnormality in ocular movements. Several months later he developed difficulty in chewing,
swallowing food, and breathing. Serologic tests revealed the presence of autoantibodies
directed to receptors at the neuromuscular junction. The most likely diagnosis is:
myasthenia gravis
A patient is admitted with multiple bacterial infections and is found to have a complete absence
of C3. Which complement-mediated function would remain intact in such a patient?
None of the above
Complement is required for:
Antibody-mediated lysis of bacteria
Which of the following is associated with the development of SLE-like symptoms?
Deficiencies in C1, C4, or C2
Activated fragments of C5 can lead to all of the following except:
Attachment of lymphocytes to macrophages
The alternative pathway of complement activation is characterized by all of the following
except:
Activation of C4
DAF regulates the complement system to prevent complement-mediated lysis of cells. This
involves:
Dissociation of the C3 convertase complex
The following activate(s) the alternative pathway of complement:
lipopolysaccharides, B) some viruses and virus-infected cells, C) fungal and
yeast cell walls, D) many strains of Gram-positive bacteria
A 22-year-old male, with significant cat allergies, visits a home with multiple cats. Two hours
later, he arrives at an urgent care center with a severe exacerbation of asthma. He is treated
with a short-acting bronchodilator and epinephrine. Initially, his symptoms resolved after
treatment; however, 8 hours later he is forced to go the emergency room with another
exacerbation. What is the most likely cause of his symptoms?
Eosinophil and basophil infiltration leading to the release of proinflammatory mediators
A 21-year old male who is allergic to cat dander is exposed to a friend’s cat while wearing a
facial mask to reduce his contact with the allergen. Nevertheless, several hours later, he is
wheezing and coughing. Which of the following best explains this individual’s allergic reaction?
Mast cells in his lung degranulated following the cross-linking of allergen-specific IgE on
their surface.
The usual sequence of events in an allergic reaction is as follows:
The allergen binds to IgE fixed to mast cells.
Epinephrine
causes bronchodilation, B) is effective even after anaphylactic symptoms
commence, C) relaxes smooth muscle, D) decreases vascular permeability
A human volunteer agrees to be passively sensitized with IgE specific for a ragweed antigen
(allergen). When challenged with the allergen intradermally, he displays a typical skin reaction
due to an immediate hypersensitivity reaction. If the injection with sensitizing IgE was preceded
by an injection (at the same site) of Fc fragments of human IgE followed by intradermal injection
with allergen, which of the following outcomes would you predict?
No reaction would occur because the Fc fragments would interact with FcεR receptors
on mast cells.
The following mechanism(s) may be involved in the clinical efficacy of desensitization therapy to
treat patients with allergies to known allergens:
enhanced production of IgG, which binds allergen before it reaches mast
cells, B) skewing of T-cell responses from TH2 to TH1, C) decreased sensitivity
of mast cells and basophils to degranulation by allergen, D) decreased
production of IgE antibody
Antihistamines
Block H1 receptors and inhibit smooth muscle contraction, dilatation of small blood
vessels, and mucus production
Which of the following remains the gold standard for asthma management?
Corticosteroids
Anaphylactic reactions
evolve in minutes and abate within 30 minutes, B) may be followed by
inflammatory reactions hours later, C) are the consequences of released
pharmacologic agents, D) may involve components of mast-cell granule matrix
Graves’ disease is an example of type II hypersensitivity whose pathophysiology is best
explained by:
Disease-causing agonistic autoantibodies to cell surface receptors
Which of the following is most likely to involve a reaction to a hapten as its etiologic cause?
Hemolytic anemia following treatment with penicillin
In an experimental mouse model for the study of autoimmune hemolytic anemia, intravenous
administration of a monoclonal IgA antibody specific for a red blood cell antigen did not cause
anemia to occur. The best explanation for this observation is that:
The Fc region of the IgA antibody does not bind receptors for Fc receptors on
phagocytic cells
The glomerular lesions in immune complex disease can be visualized microscopically with a
fluorescent anti- body against:
A) IgG heavy chains, B) κ light chains, C) C1, D) C3
Immune complexes are involved in the pathogenesis of which of the following rheumatic feverassociated
diseases:
Poststreptococcal glomerulonephritis
The final damage to vessels in immune complex-mediated arthritis is due to
Lysosomal enzymes of polymorphonuclear leukocytes
Serum sickness is characterized by
Deposition of immune complexes in blood vessel walls when there is a
moderate excess of antigen B) phagocytosis of complexes by granulocytes, C)
consumption of complement, D) appearance of symptoms before free antibody
can be detected in the circulation
Type II hypersensitivity
Involves antibody-mediated destruction of cells
A patient is suspected of having farmer’s lung. A provocation test involving the inhalation of an
extract of moldy hay is performed. A sharp drop in respiratory function is noted within 10
minutes and returns to normal in 2 hours, only to fall again in another 2 hours. The most likely
explanation is that
The symptoms of farmer’s lung are complicated by an IgE-mediated reactivity to the
same antigen
Which of the following does not involve cell-mediated immunity?
Serum sickness
A positive delayed-type hypersensitivity skin reaction involves the interaction of
Antigen, antigen-sensitive T cells, and macrophages
Delayed skin reactions to an intradermal injection of antigen may be markedly decreased by
Exposure to a high dose of X-irradiation
Which of the following statements is characteristic of contact sensitivity?
Some chemicals acting as haptens induce sensitivity by covalently binding to host
proteins acting as carriers
Positive skin tests for delayed-type hypersensitivity to intradermally injected antigens indicate
that
A cell-mediated immune response has occurred
T-cell–mediated immune responses can result in
A) formation of granulomas, B) induration at the reaction site, C) rejection of a
heart transplant, D) eczema of the skin in the area of prolonged contact with a
rubberized undergarment
Which one of the following statements about the PPD skin test is true?
B, C and D are all true
An 8-month-old baby has a history of repeated Gram- positive bacterial infections. The most
probable cause for this condition is:
None of the above
A 50-year-old worker at an atomic plant who previously had a sample of his own bone marrow
cryopreserved was accidentally exposed to a minimal lethal dose of radiation. He was
subsequently transplanted with his own bone marrow. This individual can expect to:
None of the above
Which of the following immune deficiency disorders is associated exclusively with an
abnormality of the humoral immune response?
X-linked agammaglobulinemia (Bruton’s agammaglobulinemia)
A sharp increase in levels of IgG with a spike in the IgG region seen in the electrophoretic
pattern of serum proteins is an indication of:
Plasma cell myeloma
Patients with DiGeorge syndrome may fail to produce IgG in response to immunization with Tdependent
antigens because:
They have a decreased number of T helper cells
A 2-year-old child has had three episodes of pneumonia and two episodes of otitis media. All
the infections were demonstrated to be pneumococcal. Which of the following disorders is
most likely to be the cause?
B-cell deficiency
A healthy woman gave birth to a baby. The newborn infant was found to be HIV-seropositive.
This finding is most likely the result of:
Maternal HIV-specific IgG being transferred across the placenta to the baby
Immunodeficiency disease can result from a:
A) developmental defect of T lymphocytes, B) developmental defect of bone
marrow stem cells, C) defect in phagocyte function, D) defect in complement
function