III - parasites Flashcards
(30 cards)
definition of ectoparasites
parasites that live on the outside of the host
either on the skin or outgrowths of the skin
difference between CD4 Th1/2 cells
Th1 - intracellular infective agent, micro-endoparasites (macrophage driven)
Th2 - extracellular infective agents, macro-endoparasites (eosinophil driven)
what do macrophages/dendrocytes release and what does it target
IL-12
NK cells
naive T cells
Th1 cells
what do NK cells and Th1 cells release in response to IL-12 and what does it do
releases IFN-γ
activates macrophages
causes naive T cells to preferentially become Th1 cells
what do activated macrophages release
pro-inflammatory cytokines
IL-1
IL-6
TNF-α
what causes IL-12 activation in Th1/NK cells
stimulation of TLR eg.
TLR2 binds GPI
TLR9 binds parasitic dsDNA
what do a percentage of IL-12/IFN-γ induced Th1 cells activate
protozoal specific B cells
preferentially induce IgG2/IgG3 expression in B cells
in general there is MHCII activation, what does this mean
innate and inflammatory NK/macrophages are the main ones being expanded
what do macro-parasites activate
eosinophils
basophils
what do helminths induce
Th2 response via IL-4
during a macroparasitic infection, what is the purpose of the release of IL-10 and TGFβ from Th2
limit acute inflammation via macrophages
during a macroparisitic infection, what cells are prioritised to be activated
eosinophils
basophils
what is the main antibody response in a macroparisitic infection
IgE
mice - IgG1
humans - IgG4
what is the IgE concentration of the total Ig serum
0.05%
what is the high-affinity IgE receptor
FcεRI
inducible in eosinophils
expressed on mast cells and basophils
when happens when an antigen binds to IgE bound to FcεRI cells
causes cross-linking of the bound IgE
aggregation of FcεRI
degranulation and release of mediators from the cell
what is the low affinity receptor that binds IgE
CD23/ FcεRII
function of CD23/FcεRII
regulation of IgE levels
present on eosinophils, mature B cells, macrophages
what are eosinophils
small granules which contain chemical mediators
what do eosinophils contain
eosinophil peroxidase
deoxy/ribonucleases
lipase
major basic proteins
what are pre-formed mediators basophils release when activated
histamine
serotonin
heparin
what are the newly formed lipid mediators released by basophils when activated
prostaglandin D2
leukotriene C4
platelet-activating factor
what are the newly formed cytokines released by basophils when activated
eosinophil chemotactic factor
interleukin-4
what is a main function of interleukin-4
critical cytokine in production of IgE
