Bacterial Pathogenesis (Exam 1) Flashcards
_______ is secreted by living bacteria with a specific activity against hos tissues.
exotoxin
_______ is inside a bacterial cell envelope and is released when it disintegrates or dies.
endotoxin
What are “superantigens”?
surface-acting exotoxins
Superantigens bypass normal antigen presentation binding _______ to stimulate _______.
MHC
T cells
Superantigens stimulate T cells which produces what major effect?
cytokine storm (excess IL-2 production)
(T/F) Superantigens have an effect at a systemic but not a local level.
False - can be either
Locally, superantigen effects are _______, while systemically, they lead to _______.
flesh-eating
toxic shock
A-B exotoxins have A which is the ______ subunit and B which is the ______ subunit.
active
binding
Direct, “door-to-door” delivery of toxins from a bacterial cytoplasm to a eukaryotic host uses what system?
Type III secretion system
_______ is reversible variation while ________ is irreversible variation in terms of rearrangements of major surface protein genes in bacteria.
phase variation
mutation
Term for small molecule secreted by pathogens which binds a host’s iron for import into bacteria.
siderophores
Lethal pathogens have a (low/high) LD50 and ID50.
low
LD50s are (higher/lower) than ID50s.
higher
Term for adherence factors of bacteria which help them stick to host ligands.
adhesins
What is an example of an adhesin on bacteria?
fimriae/pili