Cytokines Flashcards
cytokine characteristics
usually act locally, however, on occasion, they may exhibit endocrine action
they act by binding to specific cytokine receptors on the cells that they effect
cytokines
soluble proteins secreted by the cells of innate and adaptive immunity that stimulate ( occasionally suppress ) the growth, maturation, and functioning of the cells of the immune system
lymphokines
cytokines primarily produced by lymphocytes
monokines
cytokines primarily produced by monocytes and macrophages
interleukins
cytokines produced by leukocytes that act on other leukocytes
cytokines are produced during the ___ and ___ ___ of innate and adaptive immune responses.
activation
effector phase
cytokines are active in very ___ concentrations
low
properties of cytokines
cytokine secretion is a brief, self limited event( not stored as preformed molecules) and often influence the synthesis of other cytokines
cytokine receptors
cytokines bind to specific high affinity receptors, which then triggers a series of biochemical events that influence the activities of immune cells and organs.
the expression of many cytokine receptors is regulate by ___ ____. the signal may be ___ ____ or ____ ____ to the cell
specific signal
another cytokine
antigen binding
the cytokine receptor can have ___ ___ that block the cytokine before it reaches its cellular target.
circulating forms
regulates the activity of the cytokines
individual cytokines may be produced by multiple cell types, which include:
pleitropism
redundancy
synergism
antagonism
pleiotropism
a single cytokine may have multiple activities
redundancy
a single activity can be caused by multiple cytokines
synergism
a cytokine may work best in association with another cytokine
antagonism
a cytokine may antagonize the effects of another cytokine
proinflammatory cytokines
contribute to the initiation of a wide spectrum of activities during the inflammatory responses, such as fever, acute phase response
what does proinflammatory cytokines include:
IL-1
IL-6
tumor necrosis factor- alpha
proinflammatroy cytokines act in concert with____ and ___ ___ to ensure the development of physiological responses to a wide variety of stimuli, such as microbial infections and tissue injury.
chemokines
hematopoietic cytokines
Interleukin-1 (IL-1) source
Macrophages (activated)
what are the two types of interleukin -1
IL-1 alpha (local)
IL-1 beta(endocrine)
IL-1 alpha
binds to macrophage membranes, enabling macrophages to activate lymphocytes that come in contact with them.
IL-1beta
secreted by cells,thus, most of the IL-1 found in circulation is this one.
T or F:
Both forms of Interleukin -1 bind to the same IL-1 receptor and mediate the same biological activities
T
IL-1 receptor antagonist
Third form that binds to IL-1 but is biologically inactive so that it functions as a competitive inhibitor of IL-1.
Also an endogenous regulator that serves to prevent excessive IL-1 driven inflammatory response.
Principal activities of IL-1
- lymphocyte activation
- acts on endothelial cells to increase expression of adhesion molecules that mediate leukocyte extravasation and secret chemokines that activate leukocytes
- stimulates the production of neutrophils and platelets by the bone marrow
- acute phase reaction
- nervous system- causes fever, lethargy malaise and lack of appetite
- initiates metabolic wasting( mobilization of aa from muscle)
acute phase reaction
stimulates hepatocytes to synthesize increased levels of acute phase proteins in response to inflamation
fever
IL-1 acts on the thermoregulatory center in the anterior hypothalamus, resulting in prostaglandin- induced fever
Interleukin-6 (IL-6) sources
Macrophages (activated)
Interleukin-6 principal activities
- stimulates synthesis of acute phase proteins; endogenous pyrogen (fever)
- bone marrow( stimulation of hematopiesis, in concert with colony-stimulating factors, it promotes the production of neutrophils and platelets)
- T cells
- Bcells
tumor necrosis factor -alpha (TNF-alpha) sources:
most dangerous of all
Macrophages
T cells