Immuno Set 2 (Innate Immunity) Flashcards

1
Q

Which of the following DOES NOT accurately describe the complement components?

A. soluble proteins
B. made by the spleen
C. located in extracellular spaces
D. some function as proteases once activated
E. activated by a cascade of enzymatic reactions

A

B. made by the spleen

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2
Q

Which of the following TLRs do not use a signal transduction cascade involving MyD88?

A. TLR1:TLR2 
B. TLR3
C. TLR4
D. TLR2:TLR6 
E. TRL7
A

B. TLR3

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3
Q

Which of the following is an acute-phase protein that activates complement?

A. TNF-α
B. mannose-binding lectin
C. fibrinogen
D. LFA-1
E. CXCL8
A

B. mannose-binding lectin

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4
Q

Which of the following is a receptor on macrophages that is specific for PAMPs?

A. Receptor for C5a
B. Fc receptor
C. Complement receptor
D. Mannose receptor
E. ICAM-1
A

D. Mannose receptor

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5
Q

A 4-year-old girl stepped on a rusty nail in her backyard. Two days later, she is taken to the pediatrician because her heel is painful, red, and swollen and is warm to the touch. All of the following are mechanisms of innate immunity that may be protecting the patient against pathogenic microbes in the heel wound EXCEPT:

A. Epithelial barrier function of the skin of her foot
B. Complement proteins present in the interstitial fluids
C. Circulating anti-tetanus toxin antibodies
D. Circulating neutrophils migrating to the site of the wound
E. Soluble cytokines that induce a local inflammatory response

A

C. Circulating anti-tetanus toxin antibodies

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6
Q

Which of the following molecules is a component of NK cell granules and is important in killing of target cells?

A. P-selectin
B. Major basic protein
C. C9 complement component D. ICAM-1
E. Perforin

A

E. Perforin

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7
Q

A common strategy by which microbes survive their host’s immune responses involves changing the structures of the molecules they produce so that they are no longer recognized by the host’s immune system. This strategy, called an antigenic variation, is most likely to allow evasion of which type of immune recognition?

A. Toll-like receptor-dependent recognition of microbes by cells of the innate immune system
B. Antibody recognition of microbial cell surface molecules
C. Mannose receptor-dependent recognition of microbes by cells of the innate immune system
D. Natural killer cell inhibitory receptor recognition of class I MHC molecules on infected cells
E. T cell receptor recognition of microbial cell wall lipid antigens

A

B. Antibody recognition of microbial cell surface molecules

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8
Q

Which of the following is NOT part of the innate immune response to extracellular bacteria?

A. Alternative pathway of complement activation
B. Lectin pathway of complement activation
C. Activation of phagocytosis by Toll-like receptors
D. Natural killer cell activation
E. Inflammation

A

D. Natural killer cell activation

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9
Q

All of the following are known mechanisms by which extracellular bacteria evade the immune system EXCEPT:

A. Capsules prevent phagocytosis
B. Inhibition of class I MHC expression
C. Genetic variation of surface antigens
D. Inhibition of complement activation
E. Neutralization of reactive oxygen intermediates
A

B. Inhibition of class I MHC expression

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10
Q

Which of the following is a feature of Natural Killer (NK) cells?

A. They express antigen receptors that directly bind antigens on the surface of microbes
B. They are activated by recognizing microbial peptides bound to host class I MHC molecules
C. They kill virally infected cells by a perforin/granzyme dependent mechanism
D. Upon activation, they secrete abundant IL-4
E. They secrete natural IgM antibodies

A

C. They kill virally infected cells by a perforin/granzyme dependent mechanism

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11
Q

All of the following molecules are opsonins that facilitate efficient phagocytosis of microbes by neutrophils and macrophages EXCEPT:

A. C3b
B. C5a
C. C-reactive protein
D. IgG
E. Mannose-binding lectin
A

B. C5a

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12
Q

Toll like receptors (TLRs) located in endosomal membranes of cells recognize which of the following?

A. Nucleic acids
B. Bacterial cell wall lipoteichoic acid
C. Bacterial cell wall lipopolysaccharide
D. Uric acid crystals
E. Peptides containing N-formylmethionyl residues

A

A. Nucleic acids

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13
Q

Which of the following statements about the recognition receptors of the innate immune system, such as Toll like receptors, is correct?

A. They are encoded by genes produced by somatic recombination of gene segments that are separated in inherited germline DNA
B. Each clone of macrophages express a unique set of these receptors that differs in specificity from those receptors on all other clones of macrophages
C. They recognize pathogen associated molecular patterns, such as viral nucleic acids, bacterial cell wall constituents, and terminal mannose residues.
D. They function to neutralize microbes, but do not initiate signal transduction pathways that activate cells.
E. They undergo somatic mutation and affinity maturation in response to microbial antigens.

A

C. They recognize pathogen associated molecular patterns, such as viral nucleic acids, bacterial cell wall constituents, and terminal mannose residues.

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14
Q

Which of the following IS NOT a function of the innate immune system?

A. Rapidly respond to microbial infections by promoting acute inflammation
B. Respond to viral infections by inducing the expression of type I interferons
C. Respond to microbial infections by inducing expression of T cell costimulators on antigen presenting cells
D. Respond to damaged and dying host cells by inducing acute inflammation
E. Respond to microbial infections by inducing a state of long lived memory that prevents repeat infections by the same microbe

A

E. Respond to microbial infections by inducing a state of long lived memory that
prevents repeat infections by the same microbe

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15
Q

A child with a mutation in the gene encoding one of the polypeptide chains of the integrin LFA-1 suffers from recurrent serious bacterial and fungal infections, and the sites of infection contain
few inflammatory leukocytes. Which of the following accurately describes the required function
of host defense that is missing in this child?

A. LFA-1 on endothelial cells binds to carbohydrate ligands on neutrophils and monocytes, causing these leukocytes to stably arrest on the endothelial surface.
B. LFA-1 on neutrophils and monocytes binds to ICAM-1 on endothelial cells causing the leukocytes to stably arrest on the endothelial surface.
C. LFA-1 on leukocytes binds to chemokines in tissues, which direct leukocytes to migrate into sites of infection
D. LFA-1 on endothelial cells binds to VCAM-1 on T cells, which supports migration of activated T cells into tissues
E. LFA-1 on neutrophils binds to ICAM-1 on bacterial cell walls, which supports phagocytosis of the bacteria.

A

B. LFA-1 on neutrophils and monocytes binds to ICAM-1 on endothelial cells causing the leukocytes to stably arrest on the endothelial surface.

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16
Q

Which of the following accurately describe the function of the selectin family of adhesion molecules?

A. Selectins support low affinity rolling of leukocytes on endothelial cells
B. Endothelial selectins increase their affinity for binding to leukocytes in response
to chemokines
C. Selectins guide migration of leukocytes though interendothelial junctions
D. Selectins are expressed only on naïve T cells
E. Selectins play a direct role in clonal selection

A

A. Selectins support low affinity rolling of leukocytes on endothelial cells

17
Q

Migration of leukocytes out of the blood into muscle tissues mainly occurs in which type of vessel?

A. Arteries 
B. Arterioles 
C. Capillaries 
D. Venules 
E. Veins
A

D. Venules

18
Q

A 52-year-old man who receives radiation therapy and cytotoxic drugs for treatment of cancer sustains significant damage to his bone marrow. Which of the following changes will most likely occur?

A. Decreased production of monocytes but not B lymphocytes
B. Decreased production of B lymphocytes but not T lymphocytes
C. Decreased production of neutrophils and monocytes but not B lymphocytes
D. Decreased production of B and T lymphocytes, monocytes, neutrophils and red
blood cells
E. Normal production of all blood cells due to compensatory extramedullary
hematopoiesis

A

D. Decreased production of B and T lymphocytes, monocytes, neutrophils and red blood cells

19
Q

Which of the following can be accurately called a cytokine?

A. A cell surface antigen receptor on lymphocyte
B. An antibody secreted by a B cell
C. A protein secreted by an immune cell that activates other cells
D. A lipid secreted by a NK cell that activates a B cell
E. A nuclear protein that regulates lymphocyte gene expression

A

C. A protein secreted by an immune cell that activates other cells

20
Q

The alternative complement pathway is initiated by which of the following?

A. Spontaneous activation of C3 component of complement
B. Mannose-containing residues of glycoproteins on certain microbes.
C. Stimulation of killer activation receptors on N K cells.
D. The formation of antibody-antigen complexes.
E. Toll-like receptor binding to pathogen-associated molecular patterns.

A

A. Spontaneous activation of C3 component of complement

21
Q

Which of the following are examples of molecules that are expressed on the cell surfaces of stressed human cells that are unhealthy or abnormal?

A. a and B defensins
B. C3 convertase and properdin
C. Cytokines and chemokines
D. IFN-a and IFN-B
E. MICA and MICB
A

E. MICA and MICB

22
Q

Double-stranded RNA-dependent protein kinase mediates the action of which of the following?

A. chemokines
B. complement
C. defensins
D. NK cells
E. type I interferons
A

E. type I interferons

23
Q

A 76-year-old man is diagnosed with Escherichia coli septicemia. The initial immune response to E. coli (gram-negative bacteria) will include which of the following?

A. binding by LPS-binding proteins and LPS delivery to TLR4 on macrophages
B. formation of specific somatically generated receptors to bind E. coli
C. generation and secretion of specific antibodies to recognize E. coli
D. production of E. coli-specific cytokines by lymphocytes
E. stimulation of killer activation receptors on NK cells

A

A. binding by LPS-binding proteins and LPS delivery to TLR4 on macrophages

24
Q

During a hospital stay, a catheter was placed into the urethra of a 70-year-old male who subsequently developed cystitis (urinary bladder infection). Which of the following is most likely contributed to infection in this patient?

A. epithelial cell facilitation of molecule exchange with the environment
B. introduction of microbes into the urethra during placement of the catheter
C. mucus secretion from epithelial cells lining the urinary tract
D. pH levels in the sterile urine of the catheterized patient
E. sebaceous and sudoriferous gland secretion of sebum and sweat

A

B. introduction of microbes into the urethra during placement of the catheter

25
Q

A 30-year-old female developed vaginal candidiasis (a fungal infection) after receiving antibiotic therapy for a sinus infection. Which of the following is possible explanation for development of infection in this patient?

A. lysozyme secretion
B. mucus secretion
C. normal commensal bacteria
D. pH
E. RNases and DNases
A

C. normal commensal bacteria

26
Q

NK cells lyse Epstein-Barr virus-infected B cells with deficient MHC I expression. Which of the following initiate activation of NK cells?

A. Activation of complement receptors
B. Engagement of Fc receptors
C. Activation of KARs
D. Activation of KIRs
E. Activation of TLR3
A

C. Activation of KARs

27
Q

Influenza viruses infect humans and elicit an immune response that is often insufficient to protect the individual from sickness or death. Which of the following structures on influenza viruses allow their recognition by innate immune cells?

A. MHC I molecules
B. MHC II molecules
C. Pathogen-associated molecular patterns
D. Pattern recognition receptor
E. Somatically generated receptors
A

C. Pathogen-associated molecular patterns