IMMUNOLOGY 3 Flashcards
what are the effects of IL-1 and TNF- alpha cytokine?
induces fever, releases acute phase proteins from the liver, vascular permeability, increases adhesion to endothelium, makes chemokines, produces IL-6
what functions does IL-6 NOT perform?
production of IL-6, chemokine productions, increased adhesion to endothelium
what causes fever?
change of the hypothalamic set point
what is the mechanism for higher body temp?
peripheral vasoconstriction –> blood flows away from periphery towards the core –> less heat loss
shivering and increased metabolic rate
what are the benefits of a fever?
more effective immune mechanisms
how is the hypothalamic set-point altered
by increasing levels of pro-inflammatory cytokines
what pro-inflammatory cytokines induce fever?
IL-1 and TNF at low concentrations and IL-6 at higher concentrations
how do pro-inflammatory cytokines increase temperature?
cause elevation of prostaglandin E2 by cells in the 3rd ventricle
what does prostaglandin E2 do?
PGE2 leads to signalling that changes the hypothalamic setpoint –> reason why blockers such as tylenol are effective anti-pyretics
what cytokine in particular causes the liver to secrete acute phase proteins?
IL-6
what are acute phase proteins useful for?
acute inflammation
what is a major acute phase proteins
C- reactive protein, ferritin, hepcidin, mannose-binding lectin, serum amyloid protein A
what does C-reactive protein do?
opsonins bind to bacterial cell wall, activates C1q –> triggers classical complement pathway
why do we test for CRP?
diagnosis for inflammatory disease
what does ferritin do?
binds to serum iron with high affinity because lots of bacteria need iron to survive
what does hepcidin do?
interferes with the transport of iron to bloodstream (so bacteria cant have it)
what does Mannose binding lectin do?
PRR that initiates the lectin complement cascade
what does serum amyloid protein A do?
increases activation of inflammasome and TLRs and opsonized some gram negative bacteria
what is the major division of interferons?
group 1: interferon alpha and interferon beta
group 2: interferon gamma
what is the role of each interferon?
group 1: interfere with viral replication
group 2: activate macrophages and adaptive immune response
where are each group of interferons secreated from?
group 1: macrophages, dendritic cells, cells that have detected a virus
group 2: Th cells and NK cells
which group of interferons is more commonly found?
group 1 –> the receptor for this is found on most cells
what is the mechanism for group 1 INFs
autocrine and paracrine fashion to provide innate, quick response
how do type 1 INF interfere with viral replications?
inhibit protein translation, degrade viral mRNA, inhibit viral protein assembly
