Brucella O-chain Function Quiz

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What is the main function of the Type IV Secretion System (T4SS) in Brucella?

Promote replication in eBCVs

Trigger autophagy in the host cells

Induce acidity in phagolysosomes

Control intracellular trafficking in host macrophages (correct)

What is the role of the acidified phagosomal compartments (eBCVs) in host cells?

Maintain the acidity for bacterial survival

Provide a replicative environment for Brucella

Support bacterial egress and cell-to-cell spread

Initiate expression of T4SS genes (correct)

Where does Brucella sustain chronic intracellular persistence in the host?

Phagolysosomes

Autophagic BCVs (aBCVs)

Replicative BCVs (rBCVs) (correct)

Endoplasmic reticulum (ER)

What leads to the formation of autophagic BCVs (aBCVs) in Brucella infection?

Interactions with autophagy pathway (C) Signup and view all the answers

How do T4SS effectors contribute to Brucella immunosuppression?

Redirect intracellular trafficking (C) Signup and view all the answers

What is the role of the O-chain in Brucella's virulence?

It protects Brucella from complement and antimicrobial peptides. (C) Signup and view all the answers

Which pathway does the O-chain facilitate for Brucella's entry into host cells?

Stimulation of the endocytic pathway (C) Signup and view all the answers

Why is the Lipid A of Brucella important for immune evasion?

It prevents interactions with Toll-like receptors. (D) Signup and view all the answers

In what way do O-chains contribute to the formation of rBCV?

By facilitating the first step of rBCV formation (A) Signup and view all the answers

How do O-chains help in immune evasion by Brucella?

By inhibiting proinflammatory cytokine production (C) Signup and view all the answers

What is the main function of dendritic cells?

Capture, process, and present antigens to B and T cells (A) Signup and view all the answers

Which Brucella outer membrane protein inhibits dendritic cells from maturing?

Omp25 (C) Signup and view all the answers

How does Omp19 contribute to Brucella's virulence?

Blocks Toll-like receptor 2 (A) Signup and view all the answers

Which T4SS effector proteins of Brucella are known to block cytokine production?

BtpA (A) Signup and view all the answers

What is the role of Cyclic B Glucan (CBG) in relation to dendritic cells?

Blocks dendritic cell cytokine production (A) Signup and view all the answers

What is the role of the T4SS effector VceC in infected cells?

Induces ER stress (B) Signup and view all the answers

Which cytokine is stimulated by the unfolded protein response (UPR) triggered by Brucella infection?

Tumor necrosis factor (A) Signup and view all the answers

What immunological structure is rich in macrophages and characterized by a lymphocytic cuff made of B and T cells?

Granuloma (A) Signup and view all the answers

What is the consequence of macrophages producing inflammatory cytokines in response to Brucella infection?

Facilitates granuloma formation (B) Signup and view all the answers

Which cellular transformation can macrophages undergo within a granuloma?

Specialized transformation into other cell types (D) Signup and view all the answers

What is the role of VceC effector in Brucella infection?

Promotes inflammatory cytokine production by trophoblasts (D) Signup and view all the answers

How do T4SS effectors like BtpA and BtpB contribute to Brucella survival?

Suppress inflammation and cytokine production by dendritic cells (D) Signup and view all the answers

Why is the ability of T4SS effectors to over stimulate and suppress the host immune response crucial for Brucella survival?

To ensure enough immune response for long-term intracellular survival (D) Signup and view all the answers

What is the role of lipopolysaccharide in Brucella strains?

Contributes to the structure of LPS molecules (D) Signup and view all the answers

How do Brucella spp. modulate the host immune response for their long-term survival?

By balancing the host immune response through T4SS effectors (B) Signup and view all the answers