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Flashcards in Pathogenesis Deck (34):
1

innate immunity is ____ and ____

quick and nonspecific

2

Innate immunity is ____ and ____

quick and nonspecific

3

Innate immune cells are...

phagocytes (neutrophils and macrophages)

4

Adaptive immune cells are...

T and B cells

5

Adaptive immunity is ____ and ____

slow and specific

6

Which cells make antibodies?

B cells

7

What is a pathogenicity island?

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

8

Type 3 bacterial secretion system = ?

a virulence factor! can inject into host cells

9

How can one pathogen cause different diseases?

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

10

Role of pili in adherence?

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

11

What is facultative adherence?

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

12

Advantages of intracellular lifestyle?

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

13

Disadvantages of intracellular lifestyle?

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

14

How do enveloped viruses attach to host cell receptors?

via envelope glycoproteins

15

Do nonenveloped viruses have glycoproteins?

No!

16

HA on flu virus binds ___ on respiratory epithelial cells

sialic acid

17

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

CD4

18

How do nonenveloped viruses attach to host cell receptors?

via capsid components, i.e. spike structures

19

How do spikes on nonenveloped viruses confer diversity?

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

20

What is the purpose of antigenic variation?

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

21

Antigenic variation vs serotypes

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

22

How can some capsules evade the human immune system?

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

23

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

A = enzymatic activity
B = binding

24

Difference between alpha, beta, and gamma hemolysis?

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

25

An example of a pore-forming exotoxin is ?

hemolysin

26

Exotoxin vs endotoxin - secreted from cell?

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

27

Exotoxin vs endotoxin - chemical makeup?

Exo: polypeptide
Endo: lipopolysaccharide

28

Exotoxin vs endotoxin - relative toxicity?

Exo: very toxic
Endo: variable toxicity

29

Exotoxin vs endotoxin - relative antigenicity?

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

30

What is meant by an "exfoliative toxin?"

Literally skin peels, i.e. scalded skin syndrome

31

5 main ways pathogens can avoid clearance by immune system:

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

32

Main role of pili?

adherence

33

Main role of capsule?

anti-phagocytosis mechanism

34

Main role of toxins?

inflict cell and tissue damage