Lecture 2: Cells of the Immune System 2

Question 1

What do the Common Lymphoid Progenitors differentiate into?

Answer 1

1. NK cells
2. B cell lymphocytes
3. T cell lymphocytes

Question 2

What do the Common Myeloid Progenitors differentiate into?

Answer 2

1) Thrombocytes
2) RBC
3) Mast cells
4) Basophils
5) Neutrophils
6) Eosinophils
7) Macrophages
8) Dendritic cells

Question 3

What determines what an HSC will differentiate into?

Answer 3

cytokines

Question 4

Which 2 cytokines signal to make common myeloid progenitors?

Answer 4

1) IL-3

2) GM-CSF

Question 5

Which cytokine signals to produce common lymphoid progenitors?

Answer 5

IL-7

Question 6

After differentiating and maturing, where do immune cells go?

Answer 6

Into the blood; bits of digested pathogen are brought to lymphoid organs by other immune cells allowing for lymphocytes to find their match

Question 7

lymphocytes only go to the site of infection when ________

Answer 7

they met their specific pathogen in the lymphoid organ

Question 8

What are the 4 common lymphoid depot sites where lymphocytes meet their pathogen?

Answer 8

1) Lymph nodes
2) Mucosal lymphoid tissue
3) Spleen
4) Tonsils and Adenoids

Question 9

Route of activated lymphocyte back to the blood stream from the lymph and ultimately to the site of infection?

Answer 9

lymph drainage into thoracic duct –> left subclavian vein

Question 10

This system of matching pathogen and lymphocyte is dependent on what?

Answer 10

COOPERATION between adaptive and innate systems (innate presents pathogen to adaptive and adaptive eradicates)

Question 11

What are the most abundant white blood cells? (Which also happen to be the most important front line defense cells of innate system)

Answer 11

neutrophils

Question 12

What is the other name for neutrophils and what is the morphological hallmark of neutrophils?

Answer 12

PMNs; 3-lobed nucleus (think 3 letters, 3 lobes)

Question 13

What are the 2 methods in which neutrophils kill pathogens?

Answer 13

1) phagocytosis

2) extracellular killing via granule release (also damages nearby tissue) and NETs (neutrophil extracellular traps)

Question 14

True or false: neutrophils are long lived

Answer 14

FALSE, they usually die after one round of phagocytosis (dead neutrophils = pus)

Question 15

What is the process of antigen presentation?

Answer 15

Dendritic cell constantly sampling environment, finds pathogen, carries fragment from infection thru lymph where it meets with a T cell for “debriefing”
T cell can then become an effector cell and go out to fight battle

Question 16

Where does the lymph meet the blood stream?

Answer 16

Subclavian vein (thoracic duct empties into it)

Question 17

What makes up the myeloid family?

Answer 17

mast cell, basophil, neutrophil, eosinophil, macrophage, myeloid dendritic cell

Question 18

Which are more common, myeloid or lymphoid cells?

Answer 18

MYELOID (think granulocytes like neutrophils)

Question 19

What are the two kinds of granules present in neutrophils?

Answer 19

1) Primary (azurophilic) - direct toxic/enzymatic activity

2) Secondary - free radical formation

Question 20

Do tissues have resident populations of neutrophils?

Answer 20

NO, they are constantly circulating, only migrate to tissues during times of infection

Question 21

What kind of cells are the work horses of the adaptive immune response?

Answer 21

Macrophages

Question 22

Can macrophages recognize specific pathogens?

Answer 22

No, but they recognize CONSERVED MICROBIAL PATTERNS (like gram negative bacteria, activating macrophage TLR4)

Question 23

What innate cells initiate adaptive immunity?

Answer 23

Dendritic cells (present antigen to immune system and signal to T-cells to proliferate)

Question 24

Describe the morphology of eosinophils and their function?

Answer 24

bi-lobed nucleus, kill parasites

Question 25

Eosinophils trigger ______ cells which release histamine causing vasodilation

Answer 25

Mast

Question 26

What is the function of Mast cells?

Answer 26

release histamine and heparin (stored in granules)

mononuclear

Question 27

What effect does the release of histamine have on blood flow?

Answer 27

INCREASES it (vasodilates area)

Question 28

What are the front line defense cells of lymphoid origin?

Answer 28

Natural killer cells (have distinctive granular cytoplasm)

Question 29

Main function of NK cells?

Answer 29

To contain infection (recognizes cells that don’t look quite right like viral infections)

Question 30

When a B cell becomes activated and starts producing antibodies, what is it called?

Answer 30

plasma cell