Deck 14: The Innate Immune Response

Question 1

Which statement about skin and mucous membranes is NOT correct?

A) They are the first line of innate immunity.
B) They are the first line of adaptive immunity.
C) They act as physical barriers to infection.
D) They contain antimicrobial secretions.
E) They separate us from our environment.

Answer 1

B

Question 2

Which is not a component of innate immunity?

A) Skin
B) Antibody
C) Inflammation
D) Fever
E) Mucus membranes

Answer 2

B

Question 3

Interferons, complement, lysozyme, and lactoferrin are all examples of

A) specific antimicrobial factors.
B) immune enzymes.
C) nonspecific antimicrobial factors.
D) cytokines.
E) antipeptides.

Answer 3

C

Question 4

Allergic reactions mainly involve

A) macrophages.
B) monocytes.
C) mast cells.
D) neutrophils.
E) eosinophils.

Question 5

In which organism were phagocytes first reported?

A) Bacteria
B) Amoeba
C) Red blood cells
D) Starfish larvae
E) Humans

Question 6

Toll-like receptors

A) are cytokines, are embedded in cellular membranes, AND are part of adaptive immunity.
B) each recognize a specific "danger" molecule AND are cytokines.
C) are embedded in cellular membranes AND are part of adaptive immunity.
D) each recognize a specific "danger" molecule AND are embedded in cellular membranes.
E) each recognize a specific "danger" molecule AND are part of adaptive immunity.

Question 7

Iron

A) is required by microorganisms.
B) binds to lactoferrin.
C) is necessary for the functioning of some enzymes.
D) binds to transferrin.
E) All of the answer choices are correct.

Question 8

Skin and mucous membranes are mostly involved in

A) adaptive immunity.
B) innate immunity.
C) autoimmunity.
D) irregular immunity.
E) secondary immunity.

Question 9

The cells primarily involved in all immune responses are the

A) erythrocytes.
B) platelets.
C) leukocytes.
D) lymphocytes.
E) chondrocytes.

Question 10

The cells responsible for adaptive immunity are the

A) lymphocytes.
B) monocytes.
C) eosinophils.
D) neutrophils.
E) leukocytes.

Question 11

Which is not involved in adaptive immunity?

A) Tear flow
B) Antibody production
C) T cells
D) B cells
E) Tear flow AND B cells

Question 12

Normal microbiota

A) are the organisms that typically reside on and in your body.
B) protect against infection by pathogens.
C) enhance infection by pathogens.
D) play no role in affecting pathogen growth.
E) are the organisms that typically reside on and in your body AND protect against infection by pathogens.

Question 13

All blood cells originate from the

A) erythrocyte stem cell.
B) leukocytic stem cell.
C) eosinophilic stem cell.
D) hematopoietic stem cell.
E) osteocytes (bone cells).

Question 14

Which of the following are referred to as mononuclear phagocytes?

A) Monocytes and macrophages
B) Lymphocytes and basophils
C) Mast cells and eosinophils
D) Basophils and eosinophils
E) Neutrophils and macrophages

Question 15

Phagocytes were first discovered and named by

A) Pasteur.
B) Koch.
C) Metchnikoff.
D) Lister.
E) Hooke.

Question 16

The leukocyte that contains histamine is the

A) lymphocyte.
B) basophil.
C) monocyte.
D) macrophage.
E) eosinophil.

Question 17

In humans, the stem cells from which all blood cells arise are found in the

A) peripheral circulation.
B) bone marrow.
C) lymphatic vessels.
D) lymph nodes.
E) spleen.

Question 18

The "voices" of a cell, which carry messages, are

A) surface receptors.
B) cytokines.
C) platelets.
D) antigens.
E) adhesion molecules.

Question 19

Factors that work generically against any foreign substance entering the host are described as

A) innate immunity.
B) specific immunity.
C) irregular immunity.
D) immune metabolism.
E) adaption.

Question 20

Which of the following are phagocytic cells found in the human body?

A) Erythrocytes AND neutrophils
B) Neutrophils AND megakaryocytes
C) Neutrophils AND macrophages
D) Megakaryocytes AND leukocytes
E) Macrophages AND erythrocytes

Question 21

The key molecule upon which all complement pathways converge is ________.

A) C1
B) C2
C) C3
D) C6
E) C9

Question 22

Which of the following are most susceptible to complement lysis?

A) Gram-positive bacteria
B) Gram-negative bacteria
C) Bacteriophages
D) Prions
E) Acid-fast bacteria

Question 23

The complement pathway that is activated by binding of C3b to cell surfaces is the

A) classical pathway.
B) alternate pathway.
C) C3 pathway.
D) mucociliary pathway.
E) All of the answer choices are correct.

Question 24

The complex resulting from complement activity that leads to cell lysis is the

A) prostaglandin complex.
B) leukotriene activating complex.
C) membrane attack complex.
D) histamine complex.
E) macrophage antibody complex.

Question 25

The low molecular weight protein produced by animal cells in response to viral infections is

A) complement.
B) lysozyme.
C) histamine.
D) interferon.
E) transferrin.

Question 26

Following digestion of a microorganism by phagocytes, the debris is excreted by

A) ingestion.
B) exocytosis.
C) extrusion.
D) budding.
E) lysis.

Question 27

The cellular organelle responsible for the digestion of ingested infectious agents is the

A) endoplasmic reticulum.
B) phagolysosome.
C) Golgi apparatus.
D) lysosome.
E) peroxisome.

Question 28

The four cardinal signs of inflammation are

A) Flare, wheals, fever, cough
B) Redness, heat, swelling, pain
C) Rash, pus, heat, rubor
D) Heat, pain, vesicles, fever
E) Heat, pain, redness, fainting

Question 29

C3b is involved in

A) opsonization.
B) interferon production.
C) properdin activation.
D) endotoxin production.
E) inflammation.

Question 30

The presence of long double-stranded RNA (> 30 bp)

A) indicates infection by any virus.
B) indicates exposure to mutagens.
C) induces synthesis of interferon.
D) indicates infection by a retrovirus.
E) indicates complement activity.

Question 31

Which statement about complement proteins is False?

A) They may be activated through three different pathways.
B) They disrupt the cytoplasmic membrane of invading bacteria and foreign cells.
C) They are part of the specific immune defense system.
D) They are a group of blood proteins produced by the liver.
E) They are part of the innate immune response.

Question 32

Which of the following cytokines is most antiviral in its action?

A) Interleukin-1
B) Interleukin-2
C) Interferon
D) Tumor necrosis factor
E) Colony-stimulating factor

Question 33

A group of interacting serum proteins that provide a nonspecific defense mechanism is

A) complement.
B) interferon.
C) glycoprotein.
D) lysozyme.
E) antibody.

Question 34

Which of the following statements about interferon is incorrect?

A) It only works on a few specific types of virus.
B) It makes cells resistant to viral infection.
C) It is a species specific molecule.
D) It does not directly inactivate viruses.
E) IFNs regulate several immune responses.

Question 35

C3a and C5a are involved in

A) inflammation AND fever.
B) interferon production AND attraction of phagocytes.
C) properdin activation AND inflammation.
D) attraction of phagocytes AND properdin activation.
E) inflammation AND attraction of phagocytes.

Question 36

The complement pathway that requires antibodies to be activated is the

A) alternate pathway.
B) classical pathway.
C) properdin pathway.
D) inflammatory pathway.
E) lectin pathway.

Question 37

Interferons function to make cells

A) prevent viral replication.
B) lyse when exposed to virus.
C) non-motile when infected with virus.
D) resistant to phagocytosis.
E) form endospores.

Question 38

The complement pathway that is activated by mannan-binding protein is the

A) classical pathway.
B) alternative pathway.
C) C3 pathway.
D) lectin pathway.
E) properdin pathway.

Question 39

Which activity of the virally invaded cell triggers production of interferon?

A) Activation of rRNA
B) Movement of nuclear proteins to the cytoplasm
C) Production of glycolipids
D) Production of dsRNA
E) Production of dsDNA

Question 40

Interleukins are

A) produced by leukocytes.
B) important in both innate and adaptive immunity.
C) involved in directly killing tumor cells.
D) protein molecules.
E) produced by leukocytes AND protein molecules.

Question 41

Pattern recognition is involved in innate immunity.

Question 42

One of the strongest indications of infectious disease is

A) a rash.
B) fever.
C) pustules.
D) vesicles.
E) vomiting.

Question 43

Pyrogens are

A) fever-inducing substances.
B) fever-inhibiting substances.
C) phagocytosis-enhancing substances.
D) complement activators.
E) pus-producing substances.

Question 44

Neutrophils are the second phagocytic cell to respond to an infection.

Question 45

Gram-negative bacteria are less susceptible to complement lysis than Gram-positive bacteria.

Question 46

What two functions do phagocytes serve in immune responses?

A) Production of antibodies AND engulfment/destruction of foreign cells.
B) Engulfment/destruction of foreign cells AND alerting the other cells of the immune system to an invader.
C) Alerting the other cells of the immune system to an invader AND serving as a physical barrier against microbial invasion.
D) Production of antibodies AND serving as a physical barrier against microbial invasion.
E) Alerting the other cells of the immune system to an invader AND production of antibodies.

Question 47

All pathways of complement activation follow the same sequence after C3.

Question 48

The attraction of leukocytes to the area of inflammation is referred to as

A) parasitism.
B) infection.
C) phototaxis.
D) chemotaxis.
E) exotaxis.

Question 49

Toll-like receptors (TLRs) bind molecules on pathogens. Why is this helpful to the immune response?

A) It provides a highly specific response to very small and highly unique areas on an individual pathogenic microbe, providing the most specific and selective response possible.
B) It provides a general response to broad categories of molecules/cells that should NOT be in our system, as we don't have these molecules on our own cells.
C) These secreted molecules help bind pathogens and then direct them to receptors on the immune system cells that can eliminate them from our systems. 
D) TLRs are capable of directly lysing (destroying) the microbes, helping our immune responses by eliminating pathogens.
E) All of these statements are correct.

Question 50

Lymphocytes are the cells primarily responsible for the adaptive immune responses.

Question 51

The first kind of leukocyte lured to the site of inflammation is the

A) neutrophil.
B) monocyte.
C) macrophage.
D) basophil.
E) B cell.

Question 52

The first host response to a nonspecific tissue injury is described as

A) inflammation.
B) reaction.
C) antibodies.
D) trauma.
E) fever.

Question 53

Fever

A) inhibits bacterial growth AND speeds up the body's reactions.
B) enhances bacterial growth AND speeds up the body's reactions.
C) inhibits bacterial growth AND triggers complement activation.
D) speeds up the body's reactions AND triggers complement activation.
E) enhances bacterial growth AND triggers complement activation.

Question 54

White blood cells also called leukocytes are important in immunity.

Question 55

Mast cells are only found in the blood.

Question 56

Fever often enhances bacterial survival during an infection.

Question 57

Defensins are short antimicrobial peptides found within mucous membranes and phagocytes.

Question 58

Interferon directly interacts with and destroys viruses.

Question 59

During apoptosis, a cell will

A) die because it is damaged and, as a result, cause an inflammatory response.
B) self-destruct and, as a result, cause an inflammatory response.
C) die because it is accidentally damaged, and, as a result, cause fever.
D) self-destruct without causing an inflammatory response.
E) divide to repair damaged tissue, leading to an inflammatory response.

Question 60

How do cytokines function?

A) They are produced by several cell types and bind directly to microbes to enhance their chance of being ingested, in a process called opsonization.
B) They are secreted by lysozomes into the phagosomes of neutrophils to enhance the killing of ingested microbes within those organelles.
C) They are secreted by one cell type, then work as a series of serum proteins to produce holes in the cytoplasmic membranes of microbes to directly lyse them.
D) They are secreted by microbes that have been engulfed by phagocytes, causing those cells to produce destructive enzymes and undergo apoptosis.
E) They are secreted by one cell type, then bind to a receptor on target cell causing a signal within that cell that turns on (or off) certain genes to achieve a response.

Question 61

The body's own cells do not trigger the alternative pathway of complement system activation. Why is this?

A) Host cells produce convertase 3b which changes C3b into C3a that does not activate the complement pathway.
B) Molecules in host cell membranes bind regulatory proteins that will inactivate any C3b molecules that attach to the membrane.
C) C3b triggers the alternative pathway in prokaryotes but not in eukaryotes.
D) Molecules in host cell membranes bind regulatory proteins that will stimulate the binding of C3b molecules to bacterial cells.
E) Molecules in host cell membranes bind any MACs, deactivating them and preventing the activation of the alternative pathway.

Question 62

Which of the following is mismatched regarding protection of the body from pathogens?

A) Stomach-acid conditions and normal microbiota
B) Skin-salt, fatty acids, and normal microbiota
C) Respiratory tract-mucociliary escalator
D) Peroxidases-milk, saliva, mucus, and some phagocytes
E) Saliva-lysozyme, peroxidase, and lactoferrin

Question 63

Smoking impairs the ciliated cells of the middle portion of the respiratory tract. Many analgesic drugs (painkillers) impair peristalsis (the churning motion of the digestive tract). The result of either of these activities leads to an increased risk of infection in their respective areas. Why?

A) The actions of the cells in these areas help to propel pathogens out of the area, serving as a part of the physical barrier system. When they are impaired/slowed, bacteria and other pathogens have an easier time adhering to the tissues in the area and causing an infection.
B) Ciliated cells also line the digestive tract, and these cells secrete strong natural antibacterial compounds. When they are impaired, bacteria can more easily infect these areas.
C) Chemicals in cigarette smoke and the chemicals in painkillers impair our immune systems, making us generally more predisposed to infections (regardless of the tissue area).
D) Chemicals in cigarette smoke and the chemicals in painkillers impair the ability of our immune system cells to move into areas that are infected. As such, they can't perform their job of eliminating microbes as well as they should and infections result more easily.
E) The actions of the cells in these areas help to propel pathogens into the stomach, where they are destroyed by acid. When they are impaired/slowed, bacteria and other pathogens do not get destroyed by and can cause an infection.

Question 64

Fever allows the body to fight microbial invaders by which of the following mechanisms?

A) Fever prevents microbes with lower optimum temperatures from growing, giving the immune system time to eliminate those cells.
B) A moderate fever reduces the inflammatory response but stimulates phagocytic activity in neutrophils and eosinophils.
C) Fever increases the inflammatory response, but reduces the production of interferons unless the invader is a dsRNA virus.
D) Fever increases the multiplication of lymphocytes and enhances the release of substances that attract basophils that then engulf the microbial invader.
E) Fever plays all of these roles in the body.

Question 65

Which of the following are enzymes found in neutrophil granules, saliva, and milk that react with hydrogen peroxide to form antimicrobial compounds?

A) Peroxidases
B) Lactoferrins
C) Transferrins
D) Peroxidases AND lactoferrins
E) Lactoferrins AND transferrins

Question 66

Which of the following is NOT True of phagocytosis?

A) Phagocytic cells are recruited to the site of an injury by chemoattractants such as complement C3b. 
B) The phagocytic cell binds microbial invaders and engulfs them by means of pseudopodia, internalizing them in a phagosome.
C) If a phagocyte encounters something too large to engulf, it releases its toxic contents as a means of destroying that invader.
D) Within a phagolysosome, O₂ consumption decreases dramatically, allowing an enzyme to produce reactive oxygen species (ROS), which are toxic.
E) The phagolysosome releases undigested debris to the outside of the cell by fusing with the phagocyte's cytoplasmic membrane.

Question 67

Please identify the INCORRECT definition regarding innate immunity.

A) First line defenses-the barriers that separate and shield the interior of the body from the surrounding environment (skin and mucous membranes).
B) Sentinel cells-host cells that help the immune system detect signs of invasion by producing cytokines when their PRRs recognize an invading microbe.
C) Inflammatory response-coordinated innate response involved in containing a site of damage, localizing the response, eliminating the invader, and restoring tissue function.
D) Innate lymphoid cells-a group of lymphocytes that have increased specificity in their mechanism of antigen recognition (example: natural killer (NK) cells).
E) RIG-like receptors-a group of pattern recognition receptors within cells that recognize molecules associated with infecting viruses.

Question 68

Which of the following is least likely to be detected by pattern recognition receptors?

A) O antigen on Gram-negative bacteria
B) Peptidoglycan in Gram-positive cells
C) Flagellin and pilin
D) Double-stranded viral RNA
E) Enzymes involved in glycolysis

Question 69

Syphilis, an STI, was once treated by intentionally infecting the patient with the parasite that causes malaria, a disease characterized by repeated bouts of fever, shaking, and chills. Why might this treatment cure syphilis?

A) Malaria parasites produce strong antibacterial compounds (since they're eukaryotic in nature-they are trying to eliminate their competition for resources). This helps to eliminate ALL bacteria in and on the human body for a short period of time.
B) Malaria parasites track down and feed upon ALL bacterial cells in the human body as a part of their life cycle. This makes them a "natural antibiotic" of sorts, and highly effective at clearing the bacterial infection of syphilis.
C) One of the side effects of malarial infection is a massive overproduction of macrophages. This drives up the ability to ingest and destroy any microbe, including the bacterium that causes syphilis.
D) The effect of driving up the body temperature for periods of time can shut down the temperature-sensitive replication of the bacterium that causes syphilis. This gives the immune system time to eliminate it properly.
E) The bacteria that cause syphilis track down and destroy the protozoan that causes malaria. By doing this, the bacteria are "occupied" and do not cause damage to the human host.

Question 70

How do some pathogens prevent complement activation or avoid the effects of activated complement?

A) Some pathogens produce C5a peptidase that destroys complement C5a, a chemoattractant that recruits phagocytes to the area of infection.
B) Some pathogens hijack the host's regulatory membrane proteins that inactivate C3b, preventing the triggering of the alternative activation pathway.
C) Some pathogens produce C5a peptidase that causes destruction of phagoctyes recruited to the area of infection.
D) Some pathogens hijack the host's regulatory membrane proteins that inactivate C3b, preventing the triggering of the alternative activation pathway AND some pathogens produce C5a peptidase that destroys complement C5a, a chemoattractant that recruits phagocytes to the area of infection.
E) Some pathogens hijack the host's regulatory membrane proteins that inactivate C3b, preventing the triggering of the alternative activation pathway AND some pathogens produce C5a peptidase that causes destruction of phagoctyes recruited to the area of infection.

Question 71

Please select the correct sequence for the steps of phagocytosis:
1) Conditions in the phagosome change, increasing its antimicrobial activities.
2) The phagocytic cell binds microbial invaders and engulfs them, internalizing them in a phagosome.
3) Phagocytic cells are recruited to the site of an injury by chemoattractants. 
4) Within the phagolysosome, various factors work together to destroy an engulfed invader.
5) The phagosome fuses with enzyme-filled lysosomes, forming a phagolysosome.

A) 1, 2, 3, 4, 5
B) 2, 4, 3, 5, 1
C) 3, 2, 1, 5, 4
D) 1, 3, 5, 2, 4
E) 1, 5, 2, 4, 3

Question 72

Which of the following is a bacterial product?

A) Lactoferrin
B) Transferrin
C) Colicin
D) Defensin
E) Mucus

Question 73

Which of the following is the correct sequence of events in the interferon response?
1) IFN induces synthesis of inactive antiviral proteins (iAVPs).
2) Virus enters host cell (cell 1) and replicates, producing long dsRNA.
3) Activated AVPs induce apoptosis of infected cell.
4) dsRNA induces synthesis and secretion of IFN to neighboring cells. 
5) Entry of virus into cell armed with iAVPs (cell 2) activates these proteins.

A) 2, 4, 1, 5, 3
B) 1, 2, 3, 4, 5
C) 3, 1, 2, 5, 4
D) 5, 4, 1, 2, 3
E) 2, 1, 4, 3, 5

Question 74

Which of the following would NOT trigger an inflammatory response?

A) Activation of complement proteins.
B) Binding of microbial products to PPRs.
C) Tissue damage caused by microbial invasion.
D) Induction of antiviral protein synthesis by IFNs.
E) Release of TNF by macrophages.

Question 75

Which of the following are lymphocytes?

A) B cells
B) T cells
C) NK cells
D) B cells AND T cells
E) B cells, T cells, AND NK cells

Question 76

A cell infected by viruses may die due to the actions of interferons. The same result would occur WITHOUT interferon-any cell infected by a virus would die directly from the virus. Is there any apparent benefit to the host organism from the interferon action?

A) No; interferon is just an evolutionary leftover from a much earlier form of antiviral activity. It has no function now. Virus infections are always treated with medications.
B) Yes; when the interferon acts on a virally infected cell, it shuts down virus replication. Without interferon, the virus will eventually kill the cell, but only after it has replicated many times. IFNs may kill the host cell, but they will also prevent it from being used to replicate virus.
C) Yes; by killing host cells, the number of cells that are available targets for viral infection is limited. This is a good way of preventing viral infection.
D) No; viruses will replicate in cells regardless of the effects of interferons, so their action of killing the cell has no benefit to the host organism during the infection process.
E) Yes; IFN is needed to activate complement which stimulates otherwise phagocytes in the host so that they recognize and destroy not only the virus but also any infected cells. Without complement, all phagocytes are inert.

Question 77

How are macrophages and neutrophils similar, and how are they different?

A) Macrophages and neutrophils both circulate in the blood. Macrophages are phagocytic cells while neutrophils are granulocytes but not phagocytes.
B) Macrophages and neutrophils are both phagocytic cells. Macrophages reside in the tissues while neutrophils typically circulate in the blood.
C) Macrophages and neutrophils are both abundant cell types in tissues. Macrophages are phagocytic cells while neutrophils are not.
D) Macrophages and neutrophils are both phagocytic cells. Macrophages are granulocytes while neutrophils are effector cells.
E) Macrophages and neutrophils are both leukocytes. Macrophages are granulocytes and neutrophils are lymphocytes.

Question 78

A physician is attempting new therapies for HIV patients who are suffering from an impaired immune response. He decides to try using a recombinant form of colony-stimulating factor cytokine (CSF). Why?

A) CSF is a strong inducer of antiviral activities in our cells, and may help our immune system fight off the effects of an HIV infection for a longer period of time.
B) CSF will help to stimulate the production of new lymphocytes, the very cells that are affected by HIV. This may help to keep the patients' immune responses "normal" for a period of time.
C) CSF will hyperstimulate the activities of the macrophages, leading to aggressive ingestion and successful destruction of HIV-infected cells.
D) CSF will drive up the production of lactoferrin and transferrin, strong antiviral compounds produced in our mucus membrane secretions that trap and destroy viruses.
E) CSF is a cytokine that allows cells to communicate. If levels of CSF are elevated, HIV-infected cells can alert other healthy cells so that they produce protective IFNs.

Question 79

Please identify the mismatched pair.

A) Kupffer cells-liver
B) Microglial cells-brain
C) Alveolar macrophages-lungs
D) Mesangial macrophages-kidneys
E) Peritoneal macrophages-meninges

Question 80

Please select the True statement regarding Toll-like receptors (TLRs).

A) A number of different TLRs have been described, all of which are found in the phospholipid membranes of endosomes and phagosomes.
B) TLRs anchored in the membrane of endosomes generally detect components of the outermost layers of microbial cells, including lipopolysaccharide (LPS), lipoproteins, and flagellin.
C) TLRs allow cells to detect patterns associated with microbes, indicating that the innate immune responses involve some specificity (although not the specificity of adaptive immunity).
D) TLRs represent a very important early-warning system for viral infections. They allow any virally infected cell to alert neighboring cells that a virus is present.
E) All of these statements are True of TLRs.