Bacterial Invasion Mechanisms Quiz Part 1, Med Level
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Questions and Answers

What is the role of virulence factors in the invasion process of pathogens?

  • Prevent pathogens from producing exoenzymes
  • Allow pathogens to colonize and damage host tissues (correct)
  • Increase the likelihood of pathogens being eliminated by humoral antibodies
  • Help pathogens disseminate through local tissues

What distinguishes obligate intracellular pathogens from facultative intracellular pathogens?

  • Ability to reproduce outside of host cells
  • Tendency to produce exoenzymes
  • Inability to reproduce outside of host cells (correct)
  • Reliance on cellular immune response for elimination

What benefit do bacterial pathogens gain by living inside host cells?

  • Enhanced protection against immune system defenses (correct)
  • Reduced access to nutrients in the host cell
  • Exposure to humoral antibodies
  • Increased competition from other microbes

How do facultative intracellular pathogens differ from obligate intracellular pathogens?

<p>Obligate intracellular pathogens can only reproduce inside host cells (B)</p> Signup and view all the answers

How do pathogens utilize the host cell actin cytoskeleton to move in the cytosol of infected cells?

<p>By forming membrane protrusions (C)</p> Signup and view all the answers

What is the mechanism through which Listeria first invades host cells?

<p>Interaction of InlA and InlB with host cell surface receptors E-cadherin and Met (A)</p> Signup and view all the answers

How does Listeria escape from phagosomes before fusion with lysosomes occurs?

<p>By acting on vacuoles using LLO and PC-PLC (B)</p> Signup and view all the answers

What is the role of actin polymerization in the spreading of Listeria?

<p>Promotes cell-to-cell spreading of Listeria (D)</p> Signup and view all the answers

How does the trigger mechanism facilitate the entry of bacteria into host cells?

<p>Bacteria attach to host cell surface and deliver effector proteins (D)</p> Signup and view all the answers

What differentiates the zipper mechanism from the trigger mechanism in terms of bacterial entry into host cells?

<p>It involves the fusion of actin-driven pseudopods in a zippering process (A)</p> Signup and view all the answers

Which group of effectors play a role in inducing massive localised rearrangements of actin and plasma membrane during 'trigger'-mediated invasion of host cells?

<p>SipA, SopB, SopE2, SipC (A)</p> Signup and view all the answers

In Salmonella and Shigella invasion of intestinal epithelial cells, what process is triggered by effector molecules secreted by the pathogens?

<p>Membrane ruffling (C)</p> Signup and view all the answers

Which method does Yersinia pseudotuberculosis primarily rely on to invade host cells?

<p>'Trigger' mechanism with surface proteins (A), 'Trigger' mechanism with surface proteins (C)</p> Signup and view all the answers

What role do effector proteins play in the 'trigger' mechanism for pathogen entry into host cells?

<p>Secretion into the host cell to regulate actin dynamics (D)</p> Signup and view all the answers

How do bacterial pathogens avoid intracellular killing by lysosomes?

<p>By promoting phagosomal membrane disruption (B)</p> Signup and view all the answers

What is the role of beta-1 integrins in the infection process?

<p>Facilitating efficient translocation across the intestinal epithelial barrier (A)</p> Signup and view all the answers

How do Mycobacterium tuberculosis, Legionella pneumophila, and Salmonella evade being digested by phagocytes?

<p>By preventing phagosomal lysis (B)</p> Signup and view all the answers

Which bacterial species utilize the SPI-2 encoded T3SS-2 to prevent fusion of the phagosome with lysosomes in macrophages?

<p>Salmonella (A)</p> Signup and view all the answers

How do Listeria monocytogenes and Shigella avoid being digested by lysosomes?

<p>By preventing phagosomal lysis (B)</p> Signup and view all the answers

What is the mechanism through which Shigella escapes from the phagosome/endosome?

<p>Secretion of IpaB protein (A)</p> Signup and view all the answers

Which type of cells do a subset of intracellular pathogens disseminate within via cell-to-cell spread?

<p>Epithelial and endothelial cells (B)</p> Signup and view all the answers

What selective advantage does proliferation in a membrane-bound compartment provide to intracellular pathogens?

<p>Enhanced protection against immune recognition (A)</p> Signup and view all the answers

How do bacterial pathogens escape intracellular killing in a vacuole?

<p>Promoting vacuolar membrane disruption (D)</p> Signup and view all the answers

What is the primary function of ZIPPER during bacterial infection?

<p>Facilitating bacterial translocation across host cell barriers (D)</p> Signup and view all the answers

Which mechanism allows Salmonella to proliferate within macrophages while avoiding digestion?

<p>Preventing fusion of phagosome with lysosome (D)</p> Signup and view all the answers

How do some intracellular pathogens facilitate their escape from phagosomes?

<p>Secreting proteins that lyse the phagosome early on (B)</p> Signup and view all the answers

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