Immuno. III - Week 6 (Fungi)

Question 1

List the four types of individuals fungal infections are regularly seen in?

Answer 1

1. HIV infected patients
2. Cancer patients undergoing chemotherapy
3. Transplant patients on immunosuppressive medication
4. Patients taking long term corticosteriods

Question 2

Define Fungi

Answer 2

Ubiquitous eukaryotic microorganisms which act as decomposers, pathogens, carbon cycling in soil and mediate mineral nutrition in plants and can be opportunistic

Question 3

What are fungal diseases called?

Answer 3

Myscoses

Question 4

What are the three characteristics of fungal diseases?

Answer 4

1. site of infection
2. route of infection
3. virulence

Question 5

State and describe the four subtypes of site of infection

Answer 5

1. Superficial mycoses
   a. caused by dermatophytes
   b. found in non-living keratinised components of skin, hair and nails
2. Subcutaneous mycoses
   a. caused by saprohytic fungi
   b. chronic nodules and ulcers in subcutaneous tissues after trauma
3. Respiratory mycoses
   a. soil saprophytes
   b. acute lung infections or granulomatous lesions
4. Candidiasis
   a. Candida albicans
   b. Superficial infections of the skin and mucosal membranes

Question 6

List and describe the two subtypes of routes of infection

Answer 6

1. endogenous - fungi in the gut or human microbiota
2. Exogenous - inhaling fungi

Question 7

List and describe the 2 subtypes of virulence

Answer 7

1. Primary - pathogenic organism
2. Opportunistic - commensal organism

Question 8

List and describe the three major components of the fungal cell wall

Answer 8

1. B-glycans
   a. Beta1,3 (scaffolding)
   b. Beta1,6 (branches)
2. Chitin (Structural stability)
3. Mannans (linked to proteins)

Question 9

What signalling molecule activates antifungal immune response?

Answer 9

CARD9

Question 10

Describe the Innate immune recognition of fungi

Answer 10

1. Dendritic cells and macrophages bind to fungi via PRR
2. Induction of intracellular signals or associated molecules
3. Induction leads to phagocytosis, killing mechanisms, development of adaptive immunity

Question 11

List the adaptive immune cells involved in fungal infection

Answer 11

1. Th1
2. Th17

Question 12

What function does Th1 of the adaptive system have in fungal infections?

Answer 12

Fungal clearance and inflammation

Question 13

What function does Th17 of the adaptive system have in fungal infection

Answer 13

Neutrophil recruitment and inflammation

Question 14

List and describe the three immune evasions of fungi

Answer 14

1. Stealth (hide from detection)
2. Control (activate host immune inhibitory mechanisms; guide immune system towards types that are not effective against the microorganism)
3. Attack (Produce molecules that destroy or disable host immune defences)

Question 15

Describe the pathogenesis of fungal infection

Answer 15

1. complementary structure to bind to host tissues
2. production of phospholipase, proteases, and elastase to cause tissue damage and impair host defenses
3. Thermotolerance to grow at 37 degrees
4. Ability to have different forms throughout the infection