Pathogenesis

Question 1

innate immunity is ____ and ____

Answer 1

quick and nonspecific

Question 2

Innate immunity is ____ and ____

Answer 2

quick and nonspecific

Question 3

Innate immune cells are…

Answer 3

phagocytes (neutrophils and macrophages)

Question 4

Adaptive immune cells are…

Answer 4

T and B cells

Question 5

Adaptive immunity is ____ and ____

Answer 5

slow and specific

Question 6

Which cells make antibodies?

Answer 6

B cells

Question 7

What is a pathogenicity island?

Answer 7

a section of bacterial chromosome that differs from the surrounding “ocean” of DNA sequences as a result of horizontal genetic exchange

Question 8

Type 3 bacterial secretion system = ?

Answer 8

a virulence factor! can inject into host cells

Question 9

How can one pathogen cause different diseases?

Answer 9

All pathogens have a core genome in common within their species, but the addition of variable elements (like phage DNA or plasmids) can introduce new virulence factors and accessory machinery

Question 10

Role of pili in adherence?

Answer 10

different pili have different subunits (tip of tail) that bind to different receptors

Question 11

What is facultative adherence?

Answer 11

some pathogens can have both extracellular and intracellular means of adherence/invasion depending on conditions/host

Question 12

Advantages of intracellular lifestyle?

Answer 12

protection from extracellular immune response, protection from abx, “trojan horse” transportation, get host nutrients from cytoplasm

Question 13

Disadvantages of intracellular lifestyle?

Answer 13

exposed to intracellular defenses, spatial limits on growth, limited to one host/harder to transmit to new host, inflammatory damage when host cell is damaged

Question 14

How do enveloped viruses attach to host cell receptors?

Answer 14

via envelope glycoproteins

Question 15

Do nonenveloped viruses have glycoproteins?

Answer 15

No!

Question 16

HA on flu virus binds ___ on respiratory epithelial cells

Answer 16

sialic acid

Question 17

GP120 (glycoprotein) on HIV binds ___ on host immune cells

Answer 17

CD4

Question 18

How do nonenveloped viruses attach to host cell receptors?

Answer 18

via capsid components, i.e. spike structures

Question 19

How do spikes on nonenveloped viruses confer diversity?

Answer 19

Difference in spikes –> different serotypes that bind to different receptors and determines what tissue infected

Question 20

What is the purpose of antigenic variation?

Answer 20

swap out surface antigens periodically to evade host immune responses launched against them by the host

Question 21

Antigenic variation vs serotypes

Answer 21

AV: short time scale, rapid evolution within life of a single organism or population
S: much longer time scale!

Question 22

How can some capsules evade the human immune system?

Answer 22

By being too similar to human polysaccharide antigens for immune system to distinguish between self and pathogen

Question 23

What are the functions of the A and B subunits of exotoxin?

Answer 23

A = enzymatic activity
B = binding

Question 24

Difference between alpha, beta, and gamma hemolysis?

Answer 24

alpha = partial hemolysis
beta = complete hemolysis
gamma = no hemolysis

Question 25

An example of a pore-forming exotoxin is ?

Answer 25

hemolysin

Question 26

Exotoxin vs endotoxin - secreted from cell?

Answer 26

Exo: yes, actively from viable microbes
Endo: no, part of bacterial architecture

Question 27

Exotoxin vs endotoxin - chemical makeup?

Answer 27

Exo: polypeptide
Endo: lipopolysaccharide

Question 28

Exotoxin vs endotoxin - relative toxicity?

Answer 28

Exo: very toxic
Endo: variable toxicity

Question 29

Exotoxin vs endotoxin - relative antigenicity?

Answer 29

Exo: very antigenic (triggers immune response easily)
Endo: poorly antigenic

Question 30

What is meant by an “exfoliative toxin?”

Answer 30

Literally skin peels, i.e. scalded skin syndrome

Question 31

5 main ways pathogens can avoid clearance by immune system:

Answer 31

1. protective polysaccharide coat
2. attaching to host cells/tissues
3. invading host cells
4. latency
5. changing antigenic characteristics

Question 32

Main role of pili?

Answer 32

adherence

Question 33

Main role of capsule?

Answer 33

anti-phagocytosis mechanism

Question 34

Main role of toxins?

Answer 34

inflict cell and tissue damage