Chapter 14

Which of the following would NOT trigger an inflammatory response?

Induction of antiviral protein synthesis by IFNs.

Please identify the INCORRECT definition regarding innate immunity.

Innate lymphoid cells- a group of lymphocytes that have increased specificity in their mechanism of antigen recognition. (example: natural killer (nk) cells)

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

Interferon

Which of the following statements about interferon is correct?

It only works on a few specific types of virus.

Which of the following statements about interferon is incorrect?

It only works on a few specific types of virus.

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

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.

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

Neutrophils AND macrophages

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

Stomach—acid conditions and normal microbiota.

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

interferon.

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

lectin pathway.

The cells primarily involved in all immune responses are the

leukocytes

The cells primarily involved in all immune responses are the:

leukocytes

The cells responsible for adaptive immunity are the

lymphocytes

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

neutrophil

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

nonspecific antimicrobial factors

During apoptosis, a cell will:

self-destruct without causing an inflammatory response

Iron:

-is required by microorganisms. -binds to lactoferrin. -is necessary for the functioning of some enzymes. -binds to transferrin. ALL ANSWER CHOICES ARE CORRECT

Which of the following are lymphocytes?

B cells, T cells, AND NK cells

True or False? Pattern recognition is involved in innate immunity

True

True or False? White blood cells also called leukocytes are important in immunity.

True

True or False: Gram-negative bacteria are less susceptible to complement lysis than Gram-positive bacteria.

false

True or false: Interferon directly interacts with and destroys viruses.

false

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.

2, 4, 1, 5, 3

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.

3, 2, 1, 5, 4

Iron

All are correct: is required by microorganisms binds to lactoferrin is necessary for the functioning of some enzymes binds to transferrin

One of the strongest indicators of infectious disease is

fever

Pyrogens are

fever-inducing substances

True or False? Mast cells are only found in the blood.

False

The key molecule upon which all complement pathways converge is

C3

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?

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 response "normal" for a period of time.

True or False? Neutrophils are the second phagocytic cell to respond to an infection.

False

What two functions do phagocytes serve in immune responses?

Engulfment/destruction of foreign cells AND alerting the other cells of the immune system to an invader.

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

Enzymes involved in glycolysis.

True or False? Fever often enhances bacterial survival during an infection.

False

True or False? Interferon directly interacts with and destroys viruses.

False

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

Fever prevents microbes with lower optimum temperatures from growing, giving the immune system time to eliminate those cells.

Which of the following are more susceptible to complement lysis?

Gram-negative bacteria

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

Macrophages and neutrophils are both phagocytic cells. Macrophages reside in the tissues while neutrophils typically circulate in the blood.

Phagocytes were first discovered and named by

Metchnikoff

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

Molecules in host cell membranes bind regulatory proteins that will inactivate any C3b molecules that attach to the membrane.

Which of the following are referred to as mononuclear phagocytes?

Monocytes and macrophages

Please identify the mismatched pair.

Peritoneal macrophages- meninges

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

Peroxidases

The four cardinal signs of inflammation are:

Redness, heat, swelling, pain

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

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.)

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

Some pathogens hijack the 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 chemoattract that recruits phagocytes to the area of infection.

Which is not involved in adaptive immunity?

Tear flow

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?

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.

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?

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.

Which statement about complement proteins is FALSE?

They are part of the specific immune defense system

Which statement about skin and mucous membranes is NOT correct?

They are the first line of adaptive immunity.

Which of the following is not true of phagocytosis?

Within a phagolysosome, o2 consumption decreases dramatically, allowing an enzyme to produce reactive oxygen species (ROS), which are toxic.

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?

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.

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

alternate pathway

Which is not a component of innate immunity?

antibody

Normal microbiota:

are the organisms that typically reside on and in your body AND protect against infection by pathogens.

Normal microbiota

are the organisms that typically reside on your body AND protect against infection by pathogens.

The leukocyte that contains histamine is the

basophil

The leukocyte that contains histamine is the:

basophil

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

bone marrow.

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

chemotaxis

The complement pathway that requires antibodies to be activated is the

classical pathway

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

complement

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

cytokines

Toll-like receptors:

each recognize a specific "danger" molecule AND are embedded in cellular membranes.

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

exocytosis

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

exocytosis

All blood cells originate from

hematopoietic stem cells

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

indicates synthesis of interferon

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

induces synthesis of interferon

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

inflammation

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

inflammation

C3a and C5a are involved in:

inflammation AND attraction of phagocytes.

Fever:

inhibits bacterial growth AND speeds up the body's reactions.

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

innate immunity

Skin and mucous membranes are mostly involved in

innate immunity.

Allergic reactions mainly involve:

mast cells

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

membrane attack complex

C3b is involved in

opsonization

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

phagolysosome

Interferons function to make cells

prevent viral replication

Interferons function to make cells:

prevent viral replication.

Interleukins are:

produced by leukocytes AND protein molecules.

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

production of dsRNA

In which organism were phagocytes first reported?

starfish larvae

True or false: Lymphocytes are the cells primarily responsible for the adaptive immune responses.

true

True or false: All pathways of complement activation follow the same sequence after C3.

true

True or false: Defensins are short antimicrobial peptides found within mucous membranes and phagocytes.

true

True or false: Pattern recognition is involved in innate immunity.

true