Bacteria: Virulence Factors

What is the mechanism behind anthrax toxin?

• Teamwork of 3 proteins

• Protective antigen (PA): Binds to anthrax toxin receptor > Allows EF and LF to bind

• Edema factor (EF): Induces high levels of cAMP > Disrupts water homeostasis

• Lethal factor (LF): Blocks intracellular kinases > Induces apoptosis

What is the mechanism behind Epsilon toxin?

• Binds to myelin in CNS

• > Creates pores in membrane

• > Induces ionic dysregulation

• > Cell swelling, increased membrane permeability

What is the mechanism behind Tcd A/B?

• Adds glucose to enzymes that manage cytoskeleton dynamics

• > Enzymes become dysfunctional

• > Breakdown of cytoskeleton, cell rounding, decreased integrity

What is the mechanism behind botulinum toxin?

• Inactivates protein that fuses synaptic vesicles with pre-synaptic membrane

• > Blocks the release of acetylcholine

• > Muscle can’t contract (paralysis) 

What is the mechanism behind tetanospasmin?

• Acts as an antagonists to GABA, which inhibits motor neurons

• > Muscle forever tenses (spastic paralysis)

What is the mechanism behind shiga toxin?

• Attaches to the surfaces of intestinal epithelium

• > Releases it’s own docking sites

• > Penetrate epithelial cell

• > Inactivates ribosomes

• > Blocks translation

What is the mechanism behind cholera toxin?

• Induces severe diarrhea

• > Induces chloride channel overactivity

• > Chloride loss

• > Water loss

• > Dehydration