25 Questions
What is the main function of the Type IV Secretion System (T4SS) in Brucella?
Control intracellular trafficking in host macrophages
What is the role of the acidified phagosomal compartments (eBCVs) in host cells?
Initiate expression of T4SS genes
Where does Brucella sustain chronic intracellular persistence in the host?
Replicative BCVs (rBCVs)
What leads to the formation of autophagic BCVs (aBCVs) in Brucella infection?
Interactions with autophagy pathway
How do T4SS effectors contribute to Brucella immunosuppression?
Redirect intracellular trafficking
What is the role of the O-chain in Brucella's virulence?
It protects Brucella from complement and antimicrobial peptides.
Which pathway does the O-chain facilitate for Brucella's entry into host cells?
Stimulation of the endocytic pathway
Why is the Lipid A of Brucella important for immune evasion?
It prevents interactions with Toll-like receptors.
In what way do O-chains contribute to the formation of rBCV?
By facilitating the first step of rBCV formation
How do O-chains help in immune evasion by Brucella?
By inhibiting proinflammatory cytokine production
What is the main function of dendritic cells?
Capture, process, and present antigens to B and T cells
Which Brucella outer membrane protein inhibits dendritic cells from maturing?
Omp25
How does Omp19 contribute to Brucella's virulence?
Blocks Toll-like receptor 2
Which T4SS effector proteins of Brucella are known to block cytokine production?
BtpA
What is the role of Cyclic B Glucan (CBG) in relation to dendritic cells?
Blocks dendritic cell cytokine production
What is the role of the T4SS effector VceC in infected cells?
Induces ER stress
Which cytokine is stimulated by the unfolded protein response (UPR) triggered by Brucella infection?
Tumor necrosis factor
What immunological structure is rich in macrophages and characterized by a lymphocytic cuff made of B and T cells?
Granuloma
What is the consequence of macrophages producing inflammatory cytokines in response to Brucella infection?
Facilitates granuloma formation
Which cellular transformation can macrophages undergo within a granuloma?
Specialized transformation into other cell types
What is the role of VceC effector in Brucella infection?
Promotes inflammatory cytokine production by trophoblasts
How do T4SS effectors like BtpA and BtpB contribute to Brucella survival?
Suppress inflammation and cytokine production by dendritic cells
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
What is the role of lipopolysaccharide in Brucella strains?
Contributes to the structure of LPS molecules
How do Brucella spp. modulate the host immune response for their long-term survival?
By balancing the host immune response through T4SS effectors
Test your knowledge on the functions of the O-chain in Brucella, including its role in immune evasion and facilitating entry into host cells. Understand how the O-chain protects the bacteria and stimulates the endocytic pathway for the formation of rBCV.
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