Mechanisms of Inflammation/Parasites Flashcards
function of inflammation
cause damage while removing harmful agents
bad clinically –> anti-inflammatory drugs; immuotherapeutic agents
good for body –> remove pathogen or toxin & repair damage
calor
heat
vasodilation of tissue due to damage - causing inflammation
Rubor
redness
RBCs entering due to tissue damage
Tumor
swelling
recruit immune cells to the site of tissue damage & due to endothelial cell damage
Dolor
Pain
Functio laesa
loss of function
inflammation
localized rxn - produces symptoms that can be internal or external
adaptive response - triggered by noxious stimuli
protective response to invading pathogen or stimuli; involved in repair
what signals lead to an immune response?
PAMPs and DAMPs binding to PRRs on immune cells
necrosis
release the contents of the cell; signal that some damage is occurring
acute inflammation
- early response; beneficial
- remove offending agent & repair tissue
- positive feedback loop
- minutes to hours
- mainly neutrophils
- mild damage
chronic inflammation
- sum of responses by a tissue against an agent
- unable to remove offending agent
- damaging effects –> fibrosis & loss of function; alveolar damage
- anti-inflammatory drugs beneficial in stopping effects
- slower - days to occur
- mainly macrophages/monocytes & lymphocytes
- severe damage
asbestos
- too big to be killed by alveolar macrophages
- irritate tissue & damage alveoli
steps of an immune reaction
- recognition of agent/damage
- recruitment of leukocytes & proteins
- destroy agent
- inflammation resolves
- tissue repaired
Hemostasis - 0 phase
1st step in immune response
vasoconstriction, platelet activation, clot formation
clot - réservoir for chemical mediators; starts recruitment & activation of leukocytes
resident cells
mast cells, macrophages, DCs
recruited cells
neutrophils, macrophages, B and T cells
NFkB pathway
associated with a lot of inflammation
- big target for drugs
- IL-1 and TNF-alpha big inflammatory mediators
chemical mediators
substance that acts on local tissue to facilitate an inflammatory response
-ex. histamine, prostaglandins, complement, etc.
exogenous sources
bacteria & viruses
endogenous sources
plasma, leukocytes, endothelial cells, fibroblasts
stages of immune response
- hemostasis
- recognition of pathogen or damage
- recruitment of leukocytes and proteins
- destroy pathogen through oxidative burst
- Inflammation resolves
- repair damaged tissue
1st phase of recruitment of leukocytes
vasoactive changes
- vasoconstriction 1st, vasodilation follows
- increase blood flow
2nd phase of recruitment of leukocytes
increase capillary permeability
-endothelial swelling or damage –> exudate & edema
extravasation
mobilizes body defenses
- margination = selectins & ICAMs help leukocytes adhere to wall
- diapedesis = leukocytes enter tissue
what do selectins, integrins, & ICAMs do?
line up on endothelial wall when there is damage
- attach to WBCs
- chemokines pull them across
- selectins (endothelium), integrins (immune cells), ICAMs (both)
role of integrins
bring immune cells through endothelial cells to tissue
-ex. CXCL1,7,8 & CCL3,5
big players in acute phase rxn - inflammation
IL-1beta, IL-6, TNF-alpha
what does IL-6 do?
induces hepatocytes to make acute phase proteins - mannon-binding lectin, fibrinogen, C-reactive protein –> opsonize bacteria & activate complement
oxidative burst
usually by neutrophils (also macrophages & DCs)
intracellular killing - release contents of cells
what helps repair tissue damage?
activation of fibroblasts - replace damaged epithelial cells
angiogenesis
role of fibroblasts
lay down collagen for repair - result in scar if not perfect
role anti-inflammatory molecules
shut down the immune response once pathogen is eliminated - apoptosis of immune cells
steps of acute inflammatory rxn
- recognizing agent/damage
- recruitment of leukocytes & proteins
- leukocytes & proteins destroy agent
- inflammation resolves
- damaged tissue repaired
where are acute phase proteins produced?
liver
-need cytokines to signal release
what mediators result in fever/inflammation
IL-1beta
IL-6
TNF-alpha
what immune cells are recruited for bacterial infection?
neutrophils
what immune cells are recruited for viral infection?
lymphocytes
what leads to fever during inflammation?
new hypothalamic set point by cytokines
Transudate
smaller holes in endothelial
- low protein and cell content (low specific gravity)
- no coagulation (clear sample)
- no inflammatory cells
- acute response