Bacteria & Fungi

Question 1

Describe the recognition of invaders.

Answer 1

1. PRRs
   -type of receptor
   -location
   -type of microbe
   *diff signaling pathways & resp

Question 2

Describe the innate immunity against bacteria.

Answer 2

1. TLRs recog PAMPs
   -IL23 -> Th17 cells -> IL17, IL6, GMCSF
   -IFNa/B -> macrophage resp -> IFNy, ROS, TNFa
   -inflammation, cytokine release
2. some bacteria high NKG2DL in cells
   -NK -> IFNy -> macrophage & DC activation
3. complement activation
   -alt & lectin pathway

Question 3

Describe the adaptive immunity against bacteria.

Answer 3

1. neutralization of toxins/enzymes
2. classical complement pathway
3. opsonization -> phagocytosis
4. destruction of intracellular bacteria -> macrophages
5. direct killing of bacteria by CTLs & NK cells
   depends on species of bacteria & mechanisms by which they cause disease

Question 4

Describe toxigenic bateria.

Answer 4

bacterial toxins -> neutralization -> ingestion by macrophage

Question 5

Describe extracellular bacteria.

Answer 5

1. bacteria in extracellular space -> opsonization -> ingestion & lysis
2. bacteria in plasma -> complement -> ingestion & lysis

Question 6

Describe intracellular bacteria.

Answer 6

pathways where the cells of the IS can kill nucleated target cells
-CTLs
-macrophages
-ADCC
>NK cells
>neutrophils
[Th1 = high IFNy & Th2 = high antibody]

Question 7

Describe intracellular bacteria (M1 & M2).

Answer 7

Question 8

Describe the evasion of the IR - avoiding phagocytosis.

Answer 8

-microbe attaches to surface to enter non phagocytic cell
-surface inhibitor of phagocytosis
-exotoxin poisons phagocyte
-capsule = poor phagocyte adherence

Question 9

Describe the evasion of the IR - avoiding complement.

Answer 9

-accelerated breakdown of complement by action of microbial products
-complement effectors from microbial cell wall
-capsule = non stable surface for alt pathway convertase
-capsule = impervious to complement MAC

Question 10

Describe fungal infections.

Answer 10

1. primary infection by fungi that affect skin
2. primary infection by dimorphic fungi that cause respiratory infections
3. secondary infections by opportunistic fungi in immunodeficient animals

Question 11

Examples of bacteria.

Answer 11

Question 12

Summary.

Answer 12