Download Invasion: Breaching Anatomical Barriers

Outline:
• Invasion
o Penetrating barriers
• Avoiding the Host Defenses
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Hiding within a host cell
Avoiding killing by CSP
Avoiding destruction by phagocytes
Avoiding antibodies
Invasion: Breaching Anatomical Barriers
• Find new niche with few competitors
• Gain access to rich nutrient supply
• 1. Skin: tough barrier, rely on skin-damaging
injuries (wounds, cuts) (Staphylococcus aureus)
• 2. Crossing mucous membrane (e.g.
intestinal epithelial cells) (Most pathogens)
Ruffling method of invasion
Avoiding the Host Defenses
1. Hiding within host cells
• Cell-to-cell Spreading
Shigella and Listeria species
Avoiding the Host Defenses
• 2. Avoiding complement killing
– Gram- bacteria are susceptible to MAC because
their outer membrane serves as a target.
– Serum resistant bacteria
– The same mechanism as the host cells use
Avoiding the Host Defenses
• Avoiding destruction by phagocytes
Avoiding the Host Defenses
• Avoiding Antibodies
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