Antiviral Immunity Flashcards
What is the main function of dendritic cells?
A) To produce antibodies
B) To present antigens to T-cells
C) To directly kill pathogens
D) To produce cytokines only
E) To activate B-cells only
B) To present antigens to T-cells
What are naïve T-cells?
T-cells that haven’t seen antigen yet
What cells can activate naïve T-cells both in vivo and in vitro?
Dendritic cells. No other cells can do this.
Which of the following is TRUE about immature dendritic cells?
A) They are efficient at antigen presentation
B) They have high expression of co-stimulatory molecules
C) They are inefficient at antigen capture
D) They are efficient at antigen capture but inefficient at antigen presentation
E) They express high levels of MHC class II on their surface
D) They are efficient at antigen capture but inefficient at antigen presentation
Which endocytic pathway in dendritic cells involves the formation of large vesicles (1-5μm) from the plasma membrane?
A) Receptor-mediated endocytosis
B) Phagocytosis
C) Macropinocytosis
D) Exocytosis
E) Caveolae-mediated endocytosis
C) Macropinocytosis
Which receptor type do dendritic cells use to recognize glycosylated proteins?
A) Toll-like receptors
B) Fc receptors
C) C-type lectins
D) Scavenger receptors
E) Heat shock protein receptors
C) C-type lectins
Which of the following is NOT a direct danger signal recognized by toll-like receptors (TLRs)?
A) Lipopolysaccharide (LPS)
B) Tumor necrosis factor-α
C) Double-stranded RNA
D) Bacterial lipoproteins
E) Flagellin
B) Tumor necrosis factor-α
What happens to E-cadherin expression during dendritic cell maturation?
A) It increases
B) It remains unchanged
C) It is reduced
D) It is completely eliminated
E) It is relocated to the nucleus
C) It is reduced
Which chemokine receptor is upregulated during dendritic cell maturation to enable homing to lymph nodes?
A) CXCR4
B) CCR5
C) CCR7
D) CXCR3
E) CCR2
C) CCR7
What is the effect of maturation on protease activity in dendritic cells?
A) Protease activity is reduced
B) Protease activity increases
C) Protease activity remains unchanged
D) All proteases are eliminated
E) Proteases are relocated to the nucleus
B) Protease activity increases
What is “cross presentation” in dendritic cells?
A) Presentation of self-antigens on MHC class II
B) Presentation of exogenous antigens on MHC class I
C) Presentation of endogenous antigens on MHC class II
D) Direct presentation of unprocessed antigens
E) Exchange of antigens between dendritic cells
B) Presentation of exogenous antigens on MHC class I
Which co-stimulatory molecules are upregulated during dendritic cell maturation?
A) CD3 and CD4
B) TCR and CD28
C) B7.1 and B7.2
D) MHC I and MHC II
E) CD36 and DEC205
C) B7.1 and B7.2
Which of the following molecules inhibits the cleavage of invariant chain by cathepsin S in immature dendritic cells?
A) Tapasin
B) Calnexin
C) Cystatin C
D) ERP57
E) β2-microglobulin
C) Cystatin C
What happens to the endosomal/lysosomal pH during dendritic cell maturation?
A) It increases (becomes more basic)
B) It decreases (becomes more acidic)
C) It remains unchanged
D) It fluctuates rapidly
E) It becomes neutral
B) It decreases (becomes more acidic)
Why is cross presentation important for initiating adaptive immunity?
A) It allows presentation of bacterial antigens only
B) It prevents autoimmunity
C) It allows dendritic cells to present antigens from pathogens that don’t directly infect them
D) It increases antibody production
E) It activates natural killer cells
C) It allows dendritic cells to present antigens from pathogens that don’t directly infect them
Where are the ligands for CCR7 expressed?
A) In bone marrow only
B) In all peripheral tissues
C) In lymphatic vessels and T cell zones of lymph nodes
D) Only in inflamed tissues
E) Only in the thymus
C) In lymphatic vessels and T cell zones of lymph nodes
Concerning immature dendritic cells:
A. They are efficient at antigen presentation;
B. They express high levels of co-stimulatory molecules;
C. They have a high endosomal/lysosomal pH;
D. They sample antigens using macropinocytosis;
E. They primarily reside in lymph nodes.
C, D
The following receptors are involved in antigen capture by dendritic cells:
A. CD3;
B. CCR7;
C. Mannose receptor;
D. CD4;
E. MHC class I.
C
Concerning toll-like receptors (TLRs) on dendritic cells:
A. TLR2 recognizes lipopolysaccharide from Gram-negative bacteria;
B. TLR4 recognizes Gram-positive bacterial cell wall compounds;
C. TLR3 recognizes double-stranded RNA;
D. TLRs inhibit dendritic cell maturation;
E. TLRs have no effect on macropinocytosis.
c
The following molecules are important for dendritic cell migration to lymph nodes:
A. E-cadherin;
B. CCR7;
C. DEC205;
D. B7.1;
E. Invariant chain.
B - CCR7
Regarding MHC class II in dendritic cells:
A. It is highly expressed on immature dendritic cells;
B. It is assembled in the MHC class II compartment (MIIC);
C. It primarily presents endogenous antigens;
D. Its expression decreases upon maturation;
E. It interacts with CD8 on T-cells.
B
Concerning cross-presentation by dendritic cells:
A. It involves presenting endogenous antigens on MHC class II;
B. It is important for activating CD4⁺ T-cells;
C. It presents exogenous antigens on MHC class I;
D. It requires proteasome-independent processing;
E. It only occurs in plasmacytoid dendritic cells.
C. It presents exogenous antigens on MHC class I
The following statements about dendritic cell maturation are correct:
A. It decreases expression of MHC class I;
B. It increases expression of B7.1 and B7.2;
C. It enhances E-cadherin expression;
D. It decreases antigen processing;
E. It reduces migration to lymph nodes.
B. It increases expression of B7.1 and B7.2;
Concerning the regulation of MHC class II in dendritic cells:
A. Cystatin C promotes invariant chain cleavage;
B. Mature dendritic cells have increased cystatin C levels;
C. Immature dendritic cells have high protease activity;
D. Mature dendritic cells have reduced endosomal pH;
E. Maturation inhibits MHC class II synthesis.
D. Mature dendritic cells have reduced endosomal pH
