5.6 Adherence and Invasion

Question 1

1. Adherence

Answer 1

Pathogens use various strategies to cause disease but often the general process of parthenogenesis is similar

Exposure to pathogens -> Adherence for skin or mucous

• > a pathogen must gain access to host tissues and multiply before damage can be done
• > bacteria and viruses that initiate infection often adhere specifically adn intimately to epithelial cells through macromolecular interactions on the surfaces of the pathogens (Bacteria: glycocalyx, capsules) and the host cell

Question 2

Microbial adherence facilitated by

Answer 2

-> microbial surface structures that bind to specific molecules on the host cell surface

Example:
bacterial adhesins and viral attachment proteins

-> adherence can be highly specific

Question 3

Listeria monocytogenes

Answer 3

• > The adhesins internalin A binds to human E-cadherin but not mouse E-cadherin
• > specifically determined by a single amino acid change between E-cadherin protein int he two host species - proline in humans- glutamate in mice

Question 4

2. Invasion

Answer 4

Exposure to pathogens -> adherence to skin or mucosa -> Invasion through wpithelium

Virulence factors : Molecules produced by pathogens that contribute to pathogenicity (in particular colonization of a niche in the host)

-> spread from initial site of adherence