Acute Inflammation Flashcards

1
Q

What is the main role of the selectin family of proteins?

A

Mediates the rolling interactions of leukocytes on the vessel wall.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do selectin molecules bind to on leukocytes?

A

The ligands for selectins are the Sialyl-Lewis X oligosaccharides that are on leukocytes. This is how they mediate the rolling effect of leukocytes along the vessel wall.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What induces release of P-selectin, and from what cell? What induces the release of E-selectin, and from what cell?

A

P-selectin release is induced by histamine from Weibel-Palade bodies on endothelial cell granules.
E-selectin release is induced by TNF and IL-1 and is from endothelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What family of proteins mediates the adhesion of leukocytes (specifically neutrophils) to the endothelium?

A

The integrins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What two molecules upregulate the expression of integrins on the vessel wall?

A

TNF and IL-1 upregulate integrins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the two main integrin proteins that are upregulated on the vessel wall?

A

VCAM-1 and ICAM-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What upregulates the expression of integrins on leukocytes?

A

C5a and LTB4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the most likely cause of leukocyte adhesion deficiency?

A

Most commonly due to autosomal recessive defect of integrins (CD18 subunit)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the physiologic process that produces exudate? Transudate?

A

Exudate is produced by an increase in permeability of small blood vessels due to ongoing inflammatory response. Transudate is produced as a result of osmotic or hydrostatic imbalances.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What cell type contains the most histamine that is released in acute inflammation?

A

Mast cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the activator of mast cells?

A
  1. trauma
  2. complement proteins C3a or C5a
  3. Antigen binding to IgE and cross linking (allergies happen via this mechanism)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where are mast cells located?

A

In the connective tissue surrounding endothelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What two lipid mediators of the acute inflammation are produced from arachidonic acid?

A

Prostaglandins and leukotrienes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What acts on the phospholipid cell membrane to release arachidonic acid?

A

phospholipase A2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What two enzymes act on arachidonic acid to create (1) prostaglandins and (2) leukotrienes?

A

(1) cyclooxygenase and (2) 5-lipoxygenase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which prostaglandin are major players in vasodilation (at the level of the arteriole) and vascular permeability (at the post-capillary venule)?

A

PGI2, PGD2, and PGE2.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What prostaglandin mediates pain and fever?

A

PGE2 (feeever)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which leukotriene is a key attractant for neutrophils during an acute inflammatory response?

19
Q

Which leukotrienes are involved in vasoconstriction, bronchospasm, and increased vascular permeability of the venules?

A

LTC4, LTD4, and LTE4

20
Q

By what mechanism do NSAIDS reduce pain?

A

Pain is mediated by the prostaglandin PGE2. NSAIDS block the COX enzymes which create prostaglandins including PGE2.

21
Q

Which eicosanoids are involved in vasodilation?

A

PGI2, PGE1, PGE2, and PGD2

22
Q

Which eicosanoids are involved in vasoconstriction?

A

TXA2, LTC4, LTD4, LTE4

23
Q

Which eicosanoids are involved in increased vascular permeability?

A

LTC4, LTD4, and LTE4 (the leukotrienes)

24
Q

Which eicosanoids are involved in chemotaxis and leukocyte adhesion?

25
What receptor is present on cells of the innate immune system and are activated by pathogen-associated molecular patterns?
Toll-like receptors
26
What is the mechanism by which toll-like receptors are activated and how they produce multiple immune mediators?
TLRs are activated when pathogen-associated molecular patterns are recognized by CD14 (a coreceptor for TLR4) on the outside of gram negative bacteria. They function by upregulation NF-kB which activates immune response genes leading to production of many mediators.
27
What are the key roles of TNF and IL-1?
Key role in induction of the systemic acute-phase response. - in endothelial activation (allowing for neutrophil arrival and function; via E selection induction and cell adhesion molecules) - for induction of fever - for production of leukocytes
28
How is fever induced in an inflammatory response?
Pyrogens (eg from bacteria) cause macrophages to release IL-1 and TNF which increase COX activity in the perivascular cells of the hypothalamus. fever is also induced
29
What 3 factors attract neutrophils to the site of injury?
IL-8, C5a, LTB4, and bacterial products
30
What is the pathway by which HOCl is generated?
O2 -> O2- via NADPH oxidase O2- -> H2O2 via superoxide dismutase H2O2 -> HOCL by myeloperoxidase (MPO)
31
What are NETs?
Neutrophil extracellular traps which provide a high concentration of antimicrobial substance sat site of infection and prevent the spread of microbes by trapping them.
32
What type of proteins enhances phagocytosis of neutrophils?
Opsonins (IgG and C3b)
33
What are the 3 ways that the complement protein C3 can become cleaved?
Classical: C1 binding to IgM or IgG bound to antigen Alternative: microbial products activate complement Lectin: mannose-binding lectin in plasma binds to carbohydrates on microbes and directly activates C1
34
Which complement protein acts as a C5 convertase to make C5a and C5b?
C3b (cleaved from C3 to make C3a and C3b)
35
How is the MAC formed?
C5b binds C6-C9 to make the MAC and lyse cells
36
Which complement proteins stimulate histamine release?
C3a, C5a and C4a
37
Which complement proteins are chemotaxic for neutrophils, eosinophils, and basophils?
C5a
38
Which complement proteins are opsins?
C3b
39
What is a factor of the coagulation cascade that is also an inactive proinflammatory protein? How does it become active?
factor XII. Activated when XII leaks out of vessels and comes in contact with extracellular components. Activates kinin and coagulation cascades
40
What does factor XIIa do that connects it to the inflammatory response?
Cleaves C3 in the complement protein system
41
What are the 3 morphological patterns of acute inflammation?
Serous inflammation Fibrinous inflammation Purulent (suppurative) inflammation
42
What characterizes serous inflammation?
Marked by the exudation of cell-poor fluid into spaces created by cell injury or into body cavities.
43
What characterizes fibrinous inflammation?
Fibrinous exudate develops when the vascular leaks are large (happens with a more pronounced increase in vascular permeability.
44
What characterizes purulent inflammation?
Characterized by production of pus, especially as in an abscess