Bacterial Invasion Strategies and Lysosome Avoidance, part 1, level easy

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What is the role of exoenzymes or toxins produced by pathogens?

Cause host tissues to reject the pathogen

Prevent adhesion to host tissues

Aid in pathogen dissemination throughout the body (correct)

Enhance the immune system response

Why are bacterial pathogens living inside host cells shielded from humoral antibodies?

Due to the presence of exoenzymes

They are primarily eliminated by a cellular immune response (correct)

Because they inhibit the production of antibodies

They actively target and destroy antibodies

What distinguishes obligate intracellular pathogens from facultative intracellular pathogens?

Method of transmission

Presence of specific virulence factors

Resistance to antibiotics

Ability to reproduce only inside host cells (correct)

Which of the following is a facultative intracellular pathogen?

Salmonella Signup and view all the answers

How do pathogens like Listeria gain access to the cytosol of adjacent cells?

By forming membrane protrusions that resolve into vacuoles Signup and view all the answers

Which surface receptors do Listeria's internalins InlA and InlB interact with during host cell invasion?

E-cadherin and Met Signup and view all the answers

How does Listeria escape from the phagosome in host cells?

Through the action of secreted proteins, LLO, and PI-PLC Signup and view all the answers

What facilitates the unidirectional movement of Listeria within host cells?

Actin polymerization Signup and view all the answers

What is the primary difference between the 'trigger' and 'zipper' mechanisms of bacterial entry into host cells?

The trigger mechanism involves effector proteins while the zipper mechanism relies on surface proteins. Signup and view all the answers

Which type of cell does the text mention as one of the most efficient in antimicrobial defense?

Macrophages and DCs Signup and view all the answers

What do Salmonella and Shigella use to induce membrane ruffles in intestinal epithelial cells?

Effector proteins Signup and view all the answers

How does Yersinia pseudotuberculosis invade host cells?

By secreting effector proteins to trigger entry Signup and view all the answers

Which bacteria use a 'zipper' mechanism for invading host cells?

Legionella pneumophila Signup and view all the answers

What is the role of the subset of T3SS1 effectors (SipA, SipC, SopB, SopE, SopE2) according to the text?

To induce massive localized rearrangements of actin and the plasma membrane Signup and view all the answers

What is the primary role of outer membrane protein invasion during the infection process?

Binding to host cell integrins Signup and view all the answers

Why is avoiding the lysosome crucial for intracellular survival strategies employed by bacteria?

To prevent being digested by lysosomal enzymes Signup and view all the answers

Which mechanism do bacteria use to subvert phagocytosis and survive within phagocytes like macrophages?

Preventing fusion of phagosome with lysosome Signup and view all the answers

How does Salmonella evade destruction within a phagocyte after being engulfed by macrophages?

Preventing fusion of phagosome with lysosome Signup and view all the answers

Which proteins are produced by Listeria monocytogenes and Shigella to escape phagosomes via lysis?

Virulence factors Signup and view all the answers

What is the significance of IpaB protein in the escape mechanism of Shigella from phagosomes?

Forms ion channels for molecule exchange Signup and view all the answers

Which bacterial species disseminate within non-phagocytic cells via cell-to-cell spread?

Rickettsia spp. Signup and view all the answers

How do most host cells eliminate pathogens taken up through phagocytosis?

Fusing phagosome with lysosome to form a digestive compartment Signup and view all the answers

What is a key challenge faced by intracellular pathogens living in vacuoles?

Remodeling vacuoles for nutrient acquisition Signup and view all the answers

What is the primary mechanism employed by bacteria to avoid intracellular killing in host cells?

Preventing fusion with lysosomes by subverting endosomal trafficking Signup and view all the answers