Host damage Flashcards
damage:
- promotes
- does what to host defenses
- facilitates
- promotes colonization in novel places
- antagonizes host defenses
- facilitates spread
a protein that kills or alters the function of a host cell
TOXIN:
a toxin that is secreted into the extracellular milieu or translocated into host cells
EXOTOXIN:
lipopolysaccharide component of
Gram-negative outer membrane; NOT a true toxin
ENDOTOXIN:
Exotoxins: two classes
A. Membrane-active toxins
B. Effectors that alter host protein activities
membrane active exotoxins 2 types
- pore formers
2. phosholipases- signaling
Role of membrane active proteins in disease
- hemolysisns- sequestration of iron
- neutrophil attack “pneumolysin”- anti-phagocytic
- destruction of phagosome membranes “listeriolysin”
proteins that target host activites how do they get across host membranes?
- AB toxins such as cholera toxin that has transferase activity
- specialized secretion systems which is only found in gram negatives
many exotoxins target
host GTPase cycle which is involved in translation, cell surface signaling, cytoskeleton activites sand secretion
roles of toxins
- promote bacterial growth by
- facilitate dissemination by
- interfere with host defenses by
- promote bacterial growth by providing access to nutrients in damaged cells
- facilitate dissemination by breaking down epithelial barriers
- interfere with host defenses by inactivating phagocytic cells
membrane active exotoxins that are pore formers are dependent on what?
concentration
mechanisms of bacterial transferases
lock host proteins in one conformation
AB toxins subunit
A- activity
B- binding
- both gram negative and positive
example of a bacterial transferase that blocks host GTPase
cholera toxin
tetanus neurotoxin intoxication leads to what type of paralysis
spastic
