Inflammation, Inflammatory Disorders, and Healing Flashcards
What is the main inflammatory cell involved in acute inflammation?
Neutrophils (polys)
What are the two main stimuli of acute inflammation?
Infection and tissue necrosis
Acute inflammation is an _________ response with _______ specificity.
- Immediate
2. Limited (innate immunity)
Where are TLR’s found?
Macrophages and dendritic cells
CD14
A TLR on macrophages - recognizes LPS on the outer membrane of GN bacteria
TLR activation results in upregulation of ______
NF-kB
True or False: TLRs are only present on cells of innate immunity.
False. TLRs are present on lymphocytes and play a role in mediating chronic inflammation as well.
Cyclooxygenase acts on arachidonic acid to generate what? What do these mediate?
PGI2, PGD2, PGE2 - vasodilation (arteriole) and inc. vasc. perm (post. cap venule)
PGE2 - fever and pain
5-lipooxygenase acts on AA to produce what? What do these mediate?
LTB4 - attracts/activates neutrophils
LTC4, LTD4, LTE4 - vasoconstriction, bronchospasm, and inc. vasc. perm
What are the 4 key mediators that attract and activate neutrophils?
- LTB4
- C5a
- IL-8
- Bacterial products
Mast cells are activated by which 3 things?
- Tissue trauma
- C3a and C5a
- Cross-linking of cell-surface IgE by antigen
Once activated, mast cells release ___________, that mediates _____________ and _________________.
- Histamine granules
- Vasodilation of arterioles
- Inc. vasc. perm at post. cap venule
What is the delayed response of mast cells?
Production of AA metabolites – leukotrienes
Classical complement pathway
C1 binds to IgG or IgM that is bound the antigen
Alternative complement pathway
Microbial products directly activate complement
Mannose-binding lectin pathway
MBL binds mannose on microorganisms and activates complement
What is the result of the activation of complement?
- C3 convertase
- C5 convertase
- Formation of MAC
What role does C3b play?
Opsonin for phagocytosis
Hageman factor
Inactive proinflammatory protein made in liver - activated upon exposure to subendothelial or tissue collagen
What does Hageman factor activate? What can this cause?
- Coagulation and fibrinolytic system - DIC in GN sepsis
- Complement
- Kinin system –> bradykinin (VD, VP, pain)
What are the cardinal signs of inflammation?
- Redness & Warmth
- Swelling
- Pain
- Fever
What mediates redness and warmth?
VD of arteriole - histamine, PGI2, PGD2, PGE2, and bradykinin
What mediates swelling?
Leakage of fluid from postcap venule into interstitial space - histamine & tissue damage
What mediates pain?
Bradykinin and PGE2 - sensitize sensory nerve endings
What mediates fever?
Pyrogens cause macrophages to release IL-1 and TNF –> Inc. COX activity in perivascular cells of hypothal –> Inc. PGE2 raises temp set point
Margination
VD slows blood flow in postcap. venule – cells marginate from center of flow to periphery
Rolling
Endothelial cells upregulate selectin to slow down neutrophils
P-selectin
Released from Weibel-Palade bodies, mediated by histamine
E-selectin
Induced by TNF and IL-1
Selectins bind ____________ on leukocyte, which results in ________ of leukocytes along the vessel wall.
- Sialyl Lewis X
2. Rolling
Leukocytes
Neutrophils and macrophages