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Flashcards in Fungal Immunity Deck (62):
1

Which phylum is the most common in causing human disease?

ascomyota

2

What is the appearance of aspergillus?

flowering- stalk with spores which germinate and form hyphae

3

Where does the cryptococcus neoformans that we breathe in all the time from?

trees and pigeons

4

Who gets cryptococcus neoformans?

people with defects in T cells e.g HIV/AIDs

5

How does cryptococcus avoid phagocytosis?

forms a capsule

6

Why does candida cause endophthalmitis?

gets stuck in microcapillaries

7

What are the opsonins in fungal infections?

pentraxin 3 and MBL

8

What type of T cells are protective in fungal infection?

Th1 and Th17

9

What are the 2 forms of candida?

yeast (circular cell form) and hyphal forms

10

Why does transitions between different forms of fungus cause problems in the host?

causes switching between protective (Th1/Th17) and non-protective (Th2) responses

11

What is aspergillus species inhaled as?

conidia

12

What form does aspergillus invade tissues as?

hyphae

13

What is the classic DAMP signalling in fungal recognition?

S100B-RAGE

14

What receptors are involved in the phagocytosis of fungi?

CTLRs, not TLRs

15

What 2 pathways are downstream of dectin-1 signalling?

inflammasome and NFkB

16

What does dectin-1 deficiency result in?

reduced IL-6 production and binding to candida--mucocutaneous fungal infections

17

What is required for NFkB activation by dectin-1?

CARD9

18

What does homozygous CARD9 mutation result in?

chronic mucocutaneous candidiasis

19

What cytokine is CARD9 required for production in response to beta-glucans?

TNFa

20

How is CARD9 invovled in T cell differentiation?

required for T cell Th17 differentiation

21

Deficiency in what TLR results in greater susceptibility to aspergillosis?

TLR4

22

What effect does plasminogen have aspergillosis defense?

directly binds to aspergillus conidia and decreases susceptibility

23

How are macrophage depleted mice affected with aspergillus fumigatus?

not any more susceptible

24

Which cells are most important in defense against invasive aspergillosis?

neutrophils - as without have no ability to clear the infection

25

What effect does NET production have on aspergillus?

traps fungus and stops from germinating

26

How does the fungal morphogenesis affect T cell differentation?

different morphotypes are phagocytsed through different modalities by DCs which results in different mautration states

27

What is the effect of coiling phagocytosis vs zipper-type on DC maturation?

coiling results in increased IL-12 production whereas zipper-type results in increased IL-4 and IL10 production

28

What type of phagocytosis is used for single cell fungal morphology?

coiling

29

What type of phagocytosis is used for hyphase forms of fungi?

zipper-type

30

How does IFNy therapy aggect invasive fungal infection?

enhances clearance by down-regulating IL-10 and causing a burst of inflammatory cytokine expression

31

What is required for NET formation?

ROS production

32

What are the emerging possibilities in the treatment of fungal infections?

IFN-y injections and adoptive T cells therapy (generation of antifungal T cells from stem cells and then injected in patients)

33

What are the main infections in patietns with CGD?

staph. and fungal infections

34

What are the common aspergillus species in the environment?

aspergillus niger and aspergillus fumigatus

35

What does the damage response framework describe?

that too weak or strong host responses to microbes can result in disease and death

36

What patients have a much higher incidence of mould allergy?

asthmatics

37

What are the 2 types of hypersensitivty reactions inovlved in ABPA?

type I and IV

38

What type of hypersensitivty reaction is hypersensitivity pneumonitis?

type III and IV

39

What is the main fungus invovled in allergy?

aspergillus

40

Why is there a suggestion that some of the damage in allergic disease to aspergillosis is autoimmune?

there is cross-reactiivity of one of hte main aspergillus allergens with human cyclophylin

41

What does ABPA stand for?

allergic bronchopulmonary aspergillosis

42

What diseases predispose to ABPA?

CF and asthma

43

What does hyphae formation allow the fungus to do?

germinate and proliferate

44

What are the obligatory criteria for ABPA?

IgE >1000; positive skin prick or aspergillus specific IgE

45

What are the radiological features of ABPA?

dilated bronchi with thick walls; ring/linear opacities; upper/central region prediliction; proximal bronchiectasis; lobar colllapse due to mucous impaction; fibrotic scarring

46

What sign is seen on CT with ABPA?

hyper dense mucus sign

47

What is the mainstya of treatment for ABPA?

steroids

48

What can be used as a steroid sparing agent in ABPA?

itraconazole

49

What is aspergillus rhinosinusitis associated with?

atopy and nasal polyposis

50

What is seen on imaging with aspergillus rhinosinusitis?

obliterated sinuses with hypo-attenuated mucosa and enhancing material

51

What are the 3 main cell wall components of funal species?

beta-glucans; chitin; mannans

52

What is the function of galectin 3 in fungal infection?

allows aphgocytes to discriminate between pathogenic and non-pathogenic yeats through recognition of beta-mannosides

53

What is the function of dectin-2 in fungal immunity?

high mannose structures that are common to many fungi and binds hyphal forms with higher affinity than yeast forms

54

What type of fungus infection are dectin-2 deficient mice susceptible to?

C.albicans but not C.neoformans

55

What other receptor does dectin-2 pair with to induce pro-inflammatory cytokines?

Fc receptor y chain

56

What is the function of DC-SIGN?

recognises N-linked mannans, and directs mannosylated fungal antigens into the DC endocytic pathway promoting antigen processing and presentation to T cells

57

What effect on fungal immunity does a polymorphism in TLR4 have ?

increased susceptibility to pulmonary aspergillosis and bloodstream candidiasis

58

What fungal disease is a polymorphism in the promoter region of TLR9 associated with?

ABPA

59

What allows fungal escape of C.albicans by dectin-1?

beta glucans are exposed in the bud scar of C.albicans yeasts but masked on hyphae

60

How does P.jireveci evade immunosurveillance?

changes the expression of major surface glycoproteins

61

What is the function of hte capsule of C.neoformans?

completely covers the fungal cell wall and prevetns recognition by PRRs and the induction of inflammation

62

What might explain how c.neoformans establishes latency and spreads in the host wtihout triggering inflammation?

are able to escape from macrophages through an expulsive mechanism that does not kill the host cell and avoids inflammation