Macrophages 1

Question 1

A macrophage is an innate immune cell present in tissue. What is it called when in blood?

Answer 1

Monocyte

Question 2

Is a monocyte in the blood an active cell?

Answer 2

No. Compare this to a neutrophil in the blood which is active.

Question 3

What is the maximum time that a monocyte will be in a blood vessel before it migrates into the tissue?

Answer 3

10 to 20 hours. It will get out sooner if there are chemotactic factors in the tissue.

Question 4

How far can a macrophage travel from the blood vessel into tissue?

Answer 4

100 micrometers

Question 5

What is the maximum distance any tissue in the body is from a blood vessel?

Answer 5

50 micrometers

Question 6

What 2 things happen after a monocyte enters the tissue for it to become a mature macrophage?

Answer 6

• It increases size by 5x
• It’s lysosomes mature

Question 7

What are macrophages called when they are in the blood?

Answer 7

Monocytes

Question 8

What are macrophages called when they are in the tissue and attached to cells?

Answer 8

Histiocytes

Question 9

What are macrophages called when they are under the skin?

Answer 9

Langerhans cells

Question 10

How many bacterial cells can a liver macrophage (in the sinuses) phagocytose in 1 seconds?

Answer 10

100
* After this the blood that ends up in the general circulation is generally pathogen free

Question 11

What are the resident macrophages of the liver called?

Answer 11

Kupffer cells

Question 12

What effect does chronic EtOH ingestion have on the enteric portal system (cells)?

Answer 12

It causes the GI barrier to be more permeable which allows more pathogens into the portal system

Question 13

When macrophages (kupffer cells) in the liver are stimulated by excess bacteria (via increased permeability from chronic EtOH) what do they release?

Answer 13

Transforming Growth Factor beta (TGF beta)

Question 14

What does TGF beta in the liver do (released by Kupffer cells)?

Answer 14

They act on stellate cells (in the liver sinusoids) which release amyloid. This is an attempt at repair (which is unnecessary

This leads to collage deposition and this leads to liver cirrhosis

Question 15

What function do macrophages in the endothelium of the spleen performs?

Answer 15

They capture old RBCs

Question 16

What are alveolar macrophages called?

Answer 16

Dust cells

Question 17

What do pulmonary macrophages (dust cells) in the alveoli do when they can’t kill a pathogen like mycobacterium TB?

Answer 17

They all fuse together and form a giant cell (aka epithelioid cell)

Has horseshoe nucleus

Question 18

The brain is immune privileged. What does this mean?

Answer 18

It means that normal immune cells and chemicals cannot enter the brain

Question 18

The brain is immune privileged. What does this mean?

Answer 18

It means that normal immune cells and chemicals cannot enter the brain

Question 19

What are the macrophages of the brain called?

Answer 19

Microglia

Question 20

What are the macrophages of the bone called?

Answer 20

Osteoclasts

Question 21

What are the 3 primary functions a the macrophage?

Answer 21

Phagocytosis
Antigen presentation
Cytokine secretion

Question 22

What does the TLR-4 along with CD14 on macrophages recognize?

Answer 22

Gram negative bacteria

Question 23

What does the TLR-2 along with CD14 on macrophages recognize?

Answer 23

Gram positive bacteria and yeasts

Question 24

What are PAMPs?

Answer 24

Pathogen Associated Molecular Patters that TLRs recognize

Question 25

How many times can a macrophage phagocytose compared to a neutrophil before it dies?

Answer 25

Macrophage = 100
Neutrophil = 20

Question 26

What can phagocytose the largest particles, macrophage or neutrophil

Answer 26

Macrophage