Chapter 18.2 Innate Immune Responses

Question 1

Innate immune responses defend against foreign cells or matter without:

Answer 1

Having to recognize specific identities

Question 2

Innate responses recognize a _____ ______ property marking the invader as foreign

Answer 2

Innate responses recognize a general molecular property marking the invader as foreign

Question 3

Innate responses include:

Answer 3

• Response to injury or infection known as inflammation
• Response to interferons (family of antiviral proteins)

Question 4

What is inflammation?

Answer 4

Local response to infection or injury

Question 5

What are two functions of inflammation?

Answer 5

destroy or inactivate foreign invaders and set the stage for tissue repair

Question 6

The key mediators of inflammation are the cells that function as_____

Answer 6

The key mediators of inflammation are the cells that function as phagocytes

Question 7

What are the three most important phagocytes for inflammation?

Answer 7

1. neutrophils
2. macrophages
3. dendritic cells

Question 8

Four common and familiar signs of tissue injury and inflammation?

Answer 8

1. local redness
2. swelling
3. heat
4. pain

Question 9

What are the two general categories that mediators of inflammation fall into?

Answer 9

1. Polypeptides (eg group known as kinins) generated in infected area by enzymatic actions of proteins that circulate in the plasma
2. Substances secreted into the extracellular fluid from cells that either already exist in infected area (mast cells or injured cells) or enter it during inflammation (neutrophils)

Question 10

Some chemical mediators cause local capillaries and venules to become permeable to _____ by inducing endothelial cells to contract = opening spaces between them

Answer 10

Some chemical mediators cause local capillaries and venules to become permeable to protein by inducing endothelial cells to contract = opening spaces between them

Question 11

What are two reasons that vasodilation coupled with the ability for capillaries and venules to become permeable to proteins is advantageous?

Answer 11

1. increased blood flow to inflamed area increases delivery of proteins and leukocytes
2. increased permeability to protein ensures that the plasma proteins that participate in inflammation can gain entry to the interstitial fluid

Question 12

Swelling in inflamed area is the result of what?

Answer 12

Edema caused by net filtration of plasma into interstitial fluid because of vasodilation and increased permeability to protein

Question 13

What is chemotaxis?

Answer 13

the process by which neutrophils begin to move out of the blood across the endothelium of capillaries and venules to enter the inflamed area at the onset of inflammation

Question 14

The messengers that mediate chemotaxis are called:

Answer 14

Chemoattractants (also called chemotaxins or chemotactic factors)

Question 15

What is an opsonin?

Answer 15

chemical factor produced by the body that can bind the phagocytes tightly to the pathogen and thereby enhance phagocytosis

Question 16

The internal, microbe-containing sac formed as a phagocyte engulfs a bacterium is called:

Answer 16

a phagosome

Question 17

When the phagosome and lysosome (which is full of hydrolytic enzymes) combine, what are they called?

Answer 17

Phagolysosome

Question 18

A family of proteins known as ______ proteins are always circulating in the blood and provide another means for extracellular killing without prior phagocytosis

Answer 18

A family of proteins known as Complement proteins are always circulating in the blood and provide another means for extracellular killing without prior phagocytosis

Question 19

the central protein in the complement cascade is:

Answer 19

C3

Question 20

Activation of C3 causes the deposition of _____ on the microbial surface

Answer 20

C3b

Question 21

C3b acts as an _____ that is recognized by receptors on phagocytes targeting the pathogen for destruction

Answer 21

C3b acts as an Opsonin- that is recognized by receptors on phagocytes targeting the pathogen for destruction

Question 22

C3b is also part of a ______ enzyme that amplifies the complement cascade and leads to the downstream development of a multiunit protein called the ________

Answer 22

C3b is also part of a proteolytic enzyme that amplifies the complement cascade and leads to the downstream development of a multiunit protein called the membrane attack complex (MAC)

Question 23

What does the MAC do?

remember MAC = Membrane attack complex

Answer 23

The MAC embeds itself in the bacterial plasma membrane (or protein coat of a virus) and forms porelike channels making it leaky = disruption to the intracellular environment kills the pathogen

Question 24

What is required to activate the first complement protein, C1, in the classical complement pathway?

Answer 24

antibodies

Question 25

The _____ ______ pathway is NOT antibody dependent and bypasses C1

Answer 25

The alternative complement pathway is NOT antibody-dependent and bypasses C1

Question 26

The alternative complement pathway is initiated as a result of interactions between ________ on the surface of the _______ and ______ ______ _____ beyond ____

Answer 26

The alternative complement pathway is initiated as a result of interactions between carbohydrates on the surface of the microbe and inactive complement molecules beyond C1

Question 27

Tissue repair:

______ (a type of connective tissue cell) that reside in the area divide rapidly and begin to secrete large quantities of collagen, and blood vessel cells proliferate in a process called _______

Answer 27

Tissue repair:

Fibroblasts (a type of connective tissue cell) that reside in the area divide rapidly and begin to secrete large quantities of collagen, and blood vessel cells proliferate in a process called angiogenesis

Question 28

________ include several proteins that nonspecifically inhibit viral replication inside host cells.

Answer 28

Type 1 interferons include several proteins that nonspecifically inhibit viral replication inside host cells

Question 29

How do type 1 interferons work?

Answer 29

• secreted by most cell types into ECF
• once in ECF type 1 interferons bind to plasma membrane receptors on the cell that secreted them as well as other cells whether they are infected or not
• Binding triggers synthesis of dozens of different antiviral proteins by the cell which interfere with the viruses ability to replicate

Question 30

Are the actions of type 1 interferons specific or non-specific?

Answer 30

Non-specific

Question 31

There is one member of the Type II interferons: ______

Answer 31

Interferon-gamma

Question 32

Interferon-gamma (the sole member of the _______) is produced by ______ cells and functions in potentiating some of the actions of _______, enhancing bacteria-killing activity of ______ and acts as a ______ in the inflammatory response

Answer 32

Interferon-gamma (the sole member of the Type II interferons) is produced by Immune cells and functions in potentiating some of the actions of type I interferons, enhancing bacteria-killing activity of macrophages and acts as a chemokine in the inflammatory response

Question 33

Innate immunity often depends upon an immune cell recognizing some general molecular feature common to many types of pathogens. These features are called:

Answer 33

Pathogen-associated molecular patterns (PAMPs)

Question 34

Which proteins function to recognize and bind to highly conserved molecular features associated with pathogens (that is the PAMPs)?

Answer 34

Toll Proteins

Question 35

Because many of the Toll proteins are plasma-membrane bound, bind to extracellular ligands and induce second messenger formation, they are referred to as _____; the family of proteins is known as _______

Answer 35

Because many of the Toll proteins are plasma-membrane bound, bind to extracellular ligands and induce second messenger formation, they are referred to as receptors; the family of proteins is known as Toll-like receptors (TLR’s)

Question 36

TLR’s (toll-like receptors) belong to a family of proteins called

Answer 36

pattern-recognition receptors (PRRs)