Cells of the immune system

Question 1

Hematopoietic cells

Answer 1

Progenitor cells from which all differentiated blood cell types arise during the process of hematopoiesis

Question 2

Where do HSCs sit in the bone marrow?

Answer 2

In a niche of osteoblasts or in sinusoidal endothelial cells

Question 3

What is the purpose of the HSCs being in a niche?

Answer 3

The niche has all the growth factors and other renewal factors that are needed

Question 4

Can HSCs be in the plasma?

Answer 4

Yes, but growth factors in the bone marrow encourage them to “home” back to the niches

Question 5

HSC maintenance is also affected by what type of cell?

Answer 5

Stromal cells

Question 6

What else do stromal cells do?

Answer 6

They push the HSCs toward differentiation to a certain type of progenitor cell

Question 7

What two types of cells can a HSC become?

Answer 7

Lymphoid or myeloid progenitor

Question 8

Common myeloid progenitors can become what types of cells?

Answer 8

Thrombocytes, red blood cells, granuloctes (e.g., mast cells), basophils, neutrophils, monocytes, or eosinophils

Question 9

What can monocytes become?

Answer 9

Dendritic cells or tissue macrophages

Question 10

Common lymphoid progenitors become what types of cells?

Answer 10

B cells, T cells, or NK cells

Question 11

Principal cytokines for myeloid progenitors

Answer 11

IL-3 and GM-CSF

Question 12

Principal cytokines for lymphoid progenitors

Answer 12

IL-7

Question 13

Principal cytokines for basophils

Answer 13

IL-4

Question 14

Principal cytokines for neutrophils

Answer 14

G-CSF

Question 15

Principal cytokines for eosinophils

Answer 15

IL-5

Question 16

Principal cytokines for monocytes/macrophages

Answer 16

GM-CSF &/or M-CSF

Question 17

Principal cytokines for dendritic cells

Answer 17

Flt3L

Question 18

Principal cytokines for B cells

Answer 18

Many, including IL-3 and IL-7

Question 19

Principal cytokines for T cells

Answer 19

IL-2 and IL-7

Question 20

How do activated lymphocytes get from lymph nodes into circulation?

Answer 20

First go through the lymph tissue to the thoracic duct, then dump into somatic circulation

Question 21

What is another name for neutrophils?

Answer 21

Polymorphonuclear neutrophilic lymphocytes (PMNs)

Question 22

What type of cell are neutrophils?

Answer 22

Granulated myeloid cells; not very acidic or basic

Question 23

What is special about neutrophils?

Answer 23

They are the most abundant cell and are the “front line” in the innate immune response

Question 24

What is the lifespan of a neutrophil?

Answer 24

Short; they usually only phagocytose once and then die

Question 25

What is extracellular killing?

Answer 25

The neutrophils, if not large enough to phagocytose the pathogen, can release antimicrobial granules out into the mileau (which will also cause local tissue damage)

Question 26

NETs

Answer 26

Neutrophil extracellular traps - contain the granular enzymes and killing molecules, but also DNA that immobilize pathogens

Question 27

Clinical representation of neutrophil invasion

Answer 27

Pus

Question 28

General information about macrophages

Answer 28

Derived from circulating monocytes Not very granular Highly active nucleus for constant transcription Have a lot of lysosomes for killing

Question 29

Can macrophages be antigen presenting cells?

Answer 29

Yes.

Question 30

Describe the immune response by macrophages over the course of infection.

Answer 30

They are originally not large in number at the infection site, but those that are present will help with recruitment. Once recruitment takes place, the presence of T cells will help with proliferation of macrophages and their response becomes much greater.

Question 31

Macrophages are strong recruiters of what process?

Answer 31

The inflammatory response

Question 32

Primary focus of dendritic cells

Answer 32

Antigen presentation

Question 33

Methods environmental sampling by dendritic cells

Answer 33

Phagocystosis or macropinocytosis

Question 34

Why are dendritic cells so important?

Answer 34

They are the link between innate response and adaptive response; without them, there would be a very weak T cell response to any foreign invader

Question 35

General features of eosinophis

Answer 35

Bilobed; absorb the eosin stains really well and turn bright pink. Neutralize and destroy parasitic invaders.

Question 36

What is contained within eosinophils, and what does that mean for the body?

Answer 36

They have a lot of enzymes and molecules that cause tissue destruction, vasodilation, and inflammatory response; must be very tightly regulated by the immune system

Question 37

Where are eosinophils usually found?

Answer 37

They are scarce, but usually reside in subepithelial connective tissue

Question 38

In what are eosinophils important clinically?

Answer 38

The allergic response

Question 39

General information about mast cells

Answer 39

Large, mononuclear cells that are filled with dark, basophilic granules mainly containing histamine.

Question 40

What is the main job of mast cells?

Answer 40

To "open vascular doors;" they degranulate vasoactive substances during an infection and cause vasodilation, increased permeability

Question 41

Basophils

Answer 41

Accomplice to mast cells and eosinophils; 2-3 lobes

Question 42

Natural killer cells - appearance

Answer 42

Large, mononuclear cells that are distinctively granular.

Question 43

Against what are NK cells aimed?

Answer 43

Viruses and tumor cells

Question 44

Why are NK cells so important?

Answer 44

They are very much like lymphocytes, but they are innate so they act quickly at killing a pathogen while the adaptive immune response is "gearing up"