Virulence, adherence, and antigenic diversity Flashcards Preview

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Flashcards in Virulence, adherence, and antigenic diversity Deck (17)
1

What are 4 big points of entry for bacteria?

1) digestive tract
2) respiratory tract
3) urogenital tract
4) conjunctiva

2

What are opa and opc?

involved in adherence and invasion

3

What 2 factors are required for adherence?

1) host cell surface receptor
2) bacterial adhesin (ex: pili)

4

What are 2 types of adhesins?

1) pili (attachment at a distance)
2) non-fimbrial adhesin (intimate attachment)

5

How are different bacteria able to infect multiple hosts?

synthesize a new adhesin for each host

6

What is an example of a cell making two kinds of pili depending on the environment?

E. Coli

Type 1 pilus (common) = liquid (bladder)
Type 2 pilus (P) = solid (kidney)

7

What is a specific strategy employed by Neisseria gonorrhea?

diversifying adhesins

as soon as cells sit down on epithelial cells, host's immune ststem starts targeting the pili as an antigen. Subpopulation of bacteria have altered their pili to escape immune surveillance

8

What is antigenic variation?

changing structures targeted by immune system

9

True or false: N/ gonorrheae can produce progeny that express pili that exhibit different epitopes than parent

true

10

What are the 2 types of pili genes?

1) PilE
2) PilS

11

What is PilE?

expressed due to having a promoter

12

What is PilS?

silent genes due to lack of promoter and incomplete gene

reservoir of antigenic diversity

13

Are PilS genes in the same orientation as PilE?

YES which is why they can be introduced into PilE in discrete units

14

What are the 2 mechanisms in which PilS fragments are introduced into PilE?

1) gene conversion
2) transformation

15

What is gene conversion?

PilS is an endogenote

silent PilS is copied and pasted into pilE (expression locus) but original pilS remains

16

Antigenicity depends on the sequence of _____ (pilE or S?)

PilE

17

How does transformation diversify pilius?

pilS is an exogenote (from a lysed donor) and recombines into the new host pilE