III - parasites Flashcards

1
Q

definition of ectoparasites

A

parasites that live on the outside of the host
either on the skin or outgrowths of the skin

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2
Q

difference between CD4 Th1/2 cells

A

Th1 - intracellular infective agent, micro-endoparasites (macrophage driven)
Th2 - extracellular infective agents, macro-endoparasites (eosinophil driven)

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3
Q

what do macrophages/dendrocytes release and what does it target

A

IL-12
NK cells
naive T cells
Th1 cells

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4
Q

what do NK cells and Th1 cells release in response to IL-12 and what does it do

A

releases IFN-γ
activates macrophages
causes naive T cells to preferentially become Th1 cells

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5
Q

what do activated macrophages release

A

pro-inflammatory cytokines
IL-1
IL-6
TNF-α

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6
Q

what causes IL-12 activation in Th1/NK cells

A

stimulation of TLR eg.
TLR2 binds GPI
TLR9 binds parasitic dsDNA

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7
Q

what do a percentage of IL-12/IFN-γ induced Th1 cells activate

A

protozoal specific B cells
preferentially induce IgG2/IgG3 expression in B cells

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8
Q

in general there is MHCII activation, what does this mean

A

innate and inflammatory NK/macrophages are the main ones being expanded

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9
Q

what do macro-parasites activate

A

eosinophils
basophils

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10
Q

what do helminths induce

A

Th2 response via IL-4

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11
Q

during a macroparasitic infection, what is the purpose of the release of IL-10 and TGFβ from Th2

A

limit acute inflammation via macrophages

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12
Q

during a macroparisitic infection, what cells are prioritised to be activated

A

eosinophils
basophils

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13
Q

what is the main antibody response in a macroparisitic infection

A

IgE
mice - IgG1
humans - IgG4

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14
Q

what is the IgE concentration of the total Ig serum

A

0.05%

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15
Q

what is the high-affinity IgE receptor

A

FcεRI
inducible in eosinophils
expressed on mast cells and basophils

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16
Q

when happens when an antigen binds to IgE bound to FcεRI cells

A

causes cross-linking of the bound IgE
aggregation of FcεRI
degranulation and release of mediators from the cell

17
Q

what is the low affinity receptor that binds IgE

A

CD23/ FcεRII

18
Q

function of CD23/FcεRII

A

regulation of IgE levels
present on eosinophils, mature B cells, macrophages

19
Q

what are eosinophils

A

small granules which contain chemical mediators

20
Q

what do eosinophils contain

A

eosinophil peroxidase
deoxy/ribonucleases
lipase
major basic proteins

21
Q

what are pre-formed mediators basophils release when activated

A

histamine
serotonin
heparin

22
Q

what are the newly formed lipid mediators released by basophils when activated

A

prostaglandin D2
leukotriene C4
platelet-activating factor

23
Q

what are the newly formed cytokines released by basophils when activated

A

eosinophil chemotactic factor
interleukin-4

24
Q

what is a main function of interleukin-4

A

critical cytokine in production of IgE

25
Q

how does filariasis larvae use the response to insect bite to its advantage

A

mast cell degranulation after bite causes vasodilation
increased vascular permeability
larvae can move readily into bloodstream

26
Q

the L3 nematode is a weak point for the larvae, how does it increase its chances of survival

A

produce proteins to block TLR’s
inhibit TCR signalling
promote Treg cells to dampen immune response

27
Q

how does L3 nematode larvae inhibit TCR signalling

A

ES-62 tetrameric glycoprotein attached to phospholipids
taken into host T cell
inhibits PKC pathway that TCR’s induce

28
Q

how does L3 modify the immune response

A

IL10 mediated class switch to IgG4
no complement activation
no ADCC activity

29
Q

how does the class switch to IgG4 improve survival chances for L3

A

IgG4 binds Fcε
blocks IgE
no basophil/eosinophil degranulation
lowers IL4/IgE formative cycle

30
Q

what are the 3 main ways leishmaniosis presents

A

cutaneous
mucocutaneous
visceral