Chapter 16

Question 1

What are the basic differences between innate and adaptive immunity.

Answer 1

• Innate immunity is the first line of defense against pathogens and is always present. It provides nonspecific protection and has no memory of specific pathogens.
• Adaptive immunity, on the other hand, is inducible, specific, and has memory of particular pathogens.

Question 2

Does first line innate immunity involve the activation of immune cells or immune proteins?

Answer 2

First line innate immunity involves physical and chemical factors, but it does not involve the activation of immune cells (neutrophils, basophils, etc). It relies on physical barriers and chemical defenses.

Question 3

What are some examples of first line innate immunity?
Be able to classify as chemical or physical.

Answer 3

• Physical: Skin, nose hairs, ciliary escalator
• Chemical: Sweat, stomach acid, saliva, sebum

Question 4

What immune cells are derived from the myeloid stem cell?

Answer 4

• Neutrophils
• Eosinophils
• Basophils
• Mast cells
• Macrophages are immune cells derived from the myeloid stem cell.

Question 5

What are the three innate immune cells that are the common phagocytes.

Answer 5

The common phagocytes in innate immunity are:
1. Neutrophils
2. Eosinophils
3. Macrophages

Question 6

Which of these immune cells is known as the ‘best’ phagocyte?

Answer 6

Among these cells, macrophages are often considered the “best” phagocytes because they are highly efficient and play a central role in phagocytosis and immune responses.

They help connect innate and adaptive immunity.

Question 7

What are TLRs? How do TLRs assist with immune defenses?

Answer 7

TLRs (Toll-like receptors) are receptor proteins on immune cells that recognize conserved molecular patterns (PAMPs) on microbes. When TLRs bind to PAMPs, they trigger immune responses, including the activation of phagocytes, inflammation, and other defense mechanisms.

Question 8

What type of microorganism is specifically targeted by eosinophils?

Answer 8

Eosinophils specifically target large microorganisms, such as helminths (parasitic worms). They release proteins to damage and kill these parasites.

Question 9

How are basophils and mast cells similar? Conversely, how are basophils and mast cells different?

Hint: They are similar in function. They are different in location.

Answer 9

Basophils and mast cells are similar in that they both contain granules filled with signaling molecules and play roles in allergic responses.

However, basophils are found in the bloodstream, while mast cells are located in body tissues.

Question 10

Which cell type found in the blood can become a macrophage?

Answer 10

Monocytes in the blood can become macrophages as they enter body tissues.

Question 11

How is a fixed macrophage different from a free macrophage?

Answer 11

• Fixed macrophages are macrophages that are embedded in body tissues, such as in the brain or skin
• Free macrophages roam tissues and gather at infection sites.

Both types are phagocytes and have antigen-presenting functions.

Question 12

What is a natural killer cell? How is it different than the other innate cells?

Answer 12

A natural killer (NK) cell is an innate lymphocyte derived from the lymphoid stem cell. Unlike other innate cells, NK cells kill abnormal human cells, such as those infected with viruses or cancer cells, without phagocytosis.

Question 13

How do perforin and granzymes kill target cells?

Answer 13

• NK cells release perforin and granzymes.
• Perforin creates holes in the target cell’s membrane, allowing granzymes to enter. Granzymes induce apoptosis (controlled cell death) in the target cell, killing it.

Question 14

What is the basic function of a dendritic cell?

Answer 14

Dendritic cells are antigen-presenting cells that capture pathogens in body tissues, migrate to immune organs, and present antigens to initiate adaptive immune responses.

Like a macrophage, this will connect the innate and adaptive immune systems.

Question 15

How are inactive complement proteins activated?

Answer 15

Inactive complement proteins are activated in response to foreign cells.
Lectin pathway will identify mannose residues.

Question 16

Which organ produces complement proteins?

Answer 16

Complement proteins are primarily produced by the liver.

Question 17

What are the shorthand terms for the two activated complement fragments?

Answer 17

The shorthand terms for the two activated complement fragments are C3a and C3b.

Question 18

Which specific complement protein is at the end of the activation cascade?

Answer 18

C3? UNCLEAR, ASK GLOVER FOR CLARIFICATION

Question 19

What are the 3 immune responses that occur after complement activation?

Answer 19

The three immune responses following complement activation are opsonization, inflammation, and cytolysis.

Question 20

What is the end result when the complement cascade from C3 to C9 is completed?

Answer 20

The end result is the formation of the membrane attack complex (MAC) composed of about a dozen C9 proteins. This MAC creates holes in the membrane of target cells, leading to cytolysis (cell lysis).

Question 21

Which cell releases interferon alpha? What cells are these interferons signaling to?

Answer 21

• Interferon alpha is released by infected cells.
• These interferons signal neighboring cells, both infected and uninfected, to enhance their resistance to viral infections.

Question 22

What are the names of a couple of enzymes that inhibit viruses?

Answer 22

Two enzymes that inhibit viruses are ribonuclease and protein kinase.

Question 23

Why are antimicrobial proteins a good defense against pathogens?

Answer 23

Antimicrobial proteins provide a broad and effective defense against pathogens. They are produced by the body in response to infection, can work together, and have stable activity across a range of pH values. There is no known microbial resistance to these proteins.

Question 24

What are the five cardinal signs of inflammation?

Answer 24

1. Pain
2. Redness
3. Immobility
4. Swelling
5. Heat

PRISH

Question 25

What is the result of histamine release at the site of injury?

Answer 25

Histamine release at the site of injury leads to vasodilation, increased permeability of blood vessels, and the associated signs of inflammation, including redness and swelling.

Question 26

What is the purpose of forming a blood clot as part of inflammation?

Answer 26

Blood clots at the site of inflammation helps block local blood vessels. This promotes the accumulation of immune cells and proteins at the site to fight infection.

Question 27

How immune cells leave the bloodstream and travel to sites of infection. What are the three formal terms?

Answer 27

1. Margination: Immune cells move to the edges of blood vessels.
2. Diapedesis: Immune cells squeeze between endothelial cells and enter tissues.
3. Chemotaxis: Immune cells follow a chemical trail to the site of infection.

Question 28

What is a pyrogen?

Answer 28

• Pyrogen is a substance that induces fever.
• Pyrogens include molecules like interleukin-1 (IL-1) and bacterial products like lipopolysaccharides (LPS).

Question 29

Why is a fever (below 104 F) beneficial?

Answer 29

A fever, typically below 104°F (40°C), is beneficial because it enhances immune responses. Elevated body temperature increases the efficiency of immune cells, inhibits the growth of many pathogens, and helps the body recover from infection more quickly.

Question 30

What is opsonization and cytolysis?

Answer 30

• Opsonization is the process of coating a microorganism or other foreign material with antibodies and complement proteins. This coating enhances phagocytosis, making the target more attractive to phagocytes.
• Cytolysis refers to the bursting or lysis of a cell. It is the destruction of foreign cells (e.g., bacteria) by creating holes in their membranes through the action of the membrane attack complex (MAC).

Opsonization: adds stickyness of microorganims so that is makes it easier for phagocytosis.
Cytolysi: C5B calls C6, C7, C8, C9 to make a hole in the cell and lyse it.

Question 31

How does a phagocyte destroy an engulfed microorganism?

Answer 31

1. Chemotaxis: Phagocytes follow chemical trail to site of insult
2. Adherence: phagocyte membrane attaches to foreign cell
3. Ingestion: pseudopodia surround the target and fuse. (Engulfed target = phagosome) Some bacteria will escape this step.
4. Digestion: the phagosome is fused with a lysosome to form phagolysosome. Some bacteria will also evade this.

Question 32

What is resistance? What is susceptible? (This is a crossover between lecture & lab)

Answer 32

• Resistance refers to the ability of the host’s immune system to withstand and combat infections and diseases. A host with a strong immune system is more resistant to pathogens.
• Susceptibility refers to the vulnerability of a host to infections and diseases. A host with a weakened or compromised immune system is more susceptible to pathogens.