Non-Specific Cellular Barrier - Innate Immunity/2LoD

Question 1

What are the 4 types of cellular barriers?

Answer 1

1. Granulocytes (neutrophils, eosinophils, basophils)
2. Macrophages
3. Dendritic cells
4. Natural Killer cells

Question 2

Where in the body are granulocytes produced?

Answer 2

In bone marrow

Question 3

What are the key differences between neutrophils and macrophages?

Answer 3

Rapid phagocytosis but not repeatedly (N) vs. slow phagocytosis but repeatedly (M); short-lived (N) vs. long-lived (M); not APCs (N) vs. are APCs (M)

Question 4

What generates enzymatic activity during neutrophil phagocytosis?

Answer 4

O2 consumption by NADPH oxidase

Question 5

What are the 3 bacterial enzymes in neutrophil granules?

Answer 5

Lysozymes, myeloperoxidase, and superoxidase

Question 6

Define and describe the differences between neutrophilia and neutropenia.

Answer 6

Neutrophilia: higher than normal neutrophils = WBCs are fighting off infection
Neutropenia: lower than normal neutrophils = infection is overpowering the I.S.

Question 7

Phagocytosis, respiratory burst, and extracellular traps (NETs) are all examples of what?

Answer 7

Of how neutrophils kill invading pathogens

Question 8

What are the 4 steps of neutrophil phagocytosis?

Answer 8

1. Chemotaxis
2. Attachment
3. Phagocytosis
4. Destruction

Question 9

What is diapedesis?

Answer 9

The process by which neutrophils migrate out of systemic circulation and enter the injured site via the gap created between endothelial cells

Question 10

How do opsonin proteins facilitate neutrophilic phagocytosis?

Answer 10

By decreasing the zeta potential between the neutrophil and antigen (both cells’ surfaces are negatively charged)

Question 11

How is a phagosome created?

Answer 11

Neutrophil engulfs the pathogen, creating a vacuum –> phagosome (pathogen trapped within neutrophil)

Question 12

What occurs during formation of the phagolysosome?

Answer 12

lysosome granules (lysozymes) fuse with the phagosome, and destruct the pathogen by secreting antimicrobial fluids

Question 13

When would eosinophilia be seen?

Answer 13

Allergies and parasitic infestations

Question 14

Describe the contents of an eosinophil granule.

Answer 14

A major basic protein (MBP) within a matrix surrounded by proteins with cytotoxic and pro-inflammatory capabilities.

Question 15

How do basophils affect blood pressure?

Answer 15

They contain a complex of vasoactive molecules which affect blood vessel diameter

Question 16

When would basophilia be seen?

Answer 16

Cancer

Question 17

Describe the 3-step process of macrophage formation.

Answer 17

Exist as monoblasts in bone marrow –> mature into monocytes/enter systemic circulation –> differentiate into macrophages when complement system recruits the phagocytic molecule into the injured tissue

Question 18

What is a distinguishing feature of an activated macrophage’s nucleus?

Answer 18

enlarged cytoplasm

Question 19

What produces interleukin (IL) proteins?

Answer 19

Macrophages and dendritic cells

Question 20

IL-1, IL-6 and TNF factor alpha are all pyrogenic cytokines. How do these proteins affect the body and fight off pathogens?

Answer 20

Increased body temp –> decreased [antigen] // decreased infectious bacterial growth.

Increasing body temp is energy-consuming, so it also makes you tired

Question 21

Why do pyrogenic cytokines reduce appetite?

Answer 21

Reduced appetite decreases the chances of bacterial entry through G.I. tract

Question 22

Pyrogenic cytokines (increase or decrease):

___ neutrophils in blood
___ motility of neutrophils
___ alternate pathway of complement system
___ lymphocyte activation

facilitating bacterial elimination by macrophages

Answer 22

“increase” for all

Question 23

An antigen causes tissue damage. What is IL-1’s role in assisting with tissue repair?

Answer 23

stimulates fibroblast proliferation which produces collagen

Question 24

T-cell and B-cell activations are tightly controlled processes (bad for I.S. to be “on” all the time; constant inflammation leads to chronic inflammatory diseases). How do they get activated?

Answer 24

By antigen-presenting cells - present a processed antigen (antigen post phagocytosis) to T cell or B cell

Question 25

Which APC is more potent- macrophages or dendritic cells?

Answer 25

Dendritic cells

Question 26

Where are antigen-presenting dendritic cells located?

Answer 26

Epithelial tissue of skin (a.k.a. Langerhans cells)

Question 27

How do natural killer (NK) cells kill infectious antigens?

Answer 27

Contain perforin and proteases (granzymes) which are secreted by NK cells and perform cytotoxic activities

Question 28

What interleukin do NK cells secrete?

Answer 28

Interleukin Tumor Necrosis Factor Alpha (IFN alpha)