Flashcards in Virulence, adherence, and antigenic diversity Deck (17)
What are 4 big points of entry for bacteria?
1) digestive tract
2) respiratory tract
3) urogenital tract
What are opa and opc?
involved in adherence and invasion
What 2 factors are required for adherence?
1) host cell surface receptor
2) bacterial adhesin (ex: pili)
What are 2 types of adhesins?
1) pili (attachment at a distance)
2) non-fimbrial adhesin (intimate attachment)
How are different bacteria able to infect multiple hosts?
synthesize a new adhesin for each host
What is an example of a cell making two kinds of pili depending on the environment?
Type 1 pilus (common) = liquid (bladder)
Type 2 pilus (P) = solid (kidney)
What is a specific strategy employed by Neisseria gonorrhea?
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
What is antigenic variation?
changing structures targeted by immune system
True or false: N/ gonorrheae can produce progeny that express pili that exhibit different epitopes than parent
What are the 2 types of pili genes?
What is PilE?
expressed due to having a promoter
What is PilS?
silent genes due to lack of promoter and incomplete gene
reservoir of antigenic diversity
Are PilS genes in the same orientation as PilE?
YES which is why they can be introduced into PilE in discrete units
What are the 2 mechanisms in which PilS fragments are introduced into PilE?
1) gene conversion
What is gene conversion?
PilS is an endogenote
silent PilS is copied and pasted into pilE (expression locus) but original pilS remains
Antigenicity depends on the sequence of _____ (pilE or S?)