Module 2 immunology and eicosanoids Flashcards
innate immune system
first response bacterial and parasitic infections granulocytes, mast cells antigen-presenting cells - macrophages and dendritic
granulocytes
neutrophil
eosinophil
basophil
antigen presenting cells (APC)
phagocytosis of bacteria/parasite
-> antigen production
activation of adaptive immune system
MHC II
Non-self antigen
APC
CD4+ T cell: bacteria
MHC I
Self antigen
CD8+ T cell: viruses
Adaptive immune system
specific response
generated: MHC protein, B or T cell
humoral immunity
B cells
cellular immunity
Tc cells: CD8: mediates cell death
Th cells: CD4: regulates cytokines, B cells
Eicosanoids
involved in inflammation and cellular signaling
- prostaglandins, prostacyclins, thromboxanes, leukotrienes
arachidonic acid
common precursor to eicosanoids
COX pathway
from arachidonic acid to
- prostaglandins
- prostacyclin
- thromboxane
lipoxygenase pathway
from arachidonic acid to
- lipoxins
- leukotrines
prostacyclin
Endothelium:
vasodilation
inhibits platelet aggregation
thromboxane
platelets:
vasoconstriction
platelet activation
PGD2: isomerase
part of COX pathway
brain and mast cells
smooth muscle contraction
inhibits platelet aggregation
PGF2: reductase
part of COX pathway uterus and lung smooth muscle contraction bronchoconstriciton abortion
PGE2: isomerase
part of COX pathway macrophages, mast cells vasodilation hyperalgesia fever diuresis immunomodulation
meds that work on COX1 and COX2
NSAID
COX2 inhibitors
glucocorticoids and lipoxygenase pathway
can inhibit arachidonic acid production
in lipoxygenase pathway arachidonic acid broken down into
leukotrienes:
LTA4: source of neutrophils
LTC4: source of mast cells, basophils, eosinophils
Lipoxygenase pathway and neutrophil actions
Activation of neutrophil: - margination - migration - degranulation - superoxide anion generation - eicosanoid synthesis Plasma exudation
lipoxygenase pathway and mast cells, basophils, eosinophils action
bronchoconstriction vasoconstriction dec. coronary blood flow dec. cardiac contractility plasma exudation
Zileuton and FLAP inhibitors
inhibit 5-liopoxygenase
prevent the breakdown of arachidonic acid to leukotrienes in lipoxygenase pathway
-> no leukotriene activation
adenosine and lipooxygenase pathway
works on LTA4 hydrolase to prevent activation of neutrophils
zafirlukast and montelukast in lipoxygenase pathway
competitively antagonize LTD4 prevent activation of mast cells, basophils, eosinophils -> prevents: - bronchoconstriction - vasoconstriction - dec. coronary blood flow - dec. cardiac contractility plasma exudation
