36: review & questions Flashcards
The kinetics of a typical CD8 T cell response to an acute virus infection in mice is shown in figure. In this example, the virus is cleared by ~day 7 post-infection, and starting at ~day 10 post-infection, the majority of the virus-specific CD8 T cells die. The death of these virus-specific CD8 T cells is:
A: Lysis from the virus infection
B: Engulfment and destruction by phagocytes
C: Natural killer cell lysis
D: Fas-induced death or cytokine withdrawal
D: Fas-induced death or cytokine withdrawal
When macrophages in a tissue encounter bacteria, they release cytokines that induce an inflammatory response. These cytokines act on other immune cells to recruit them to the site of infection and to enhance their activities. In addition, these cytokines act on the endothelial cells of the blood vessel wall to:
A: Increase their permeability,
allowing fluid and proteins to leak into tissue
B: Solidify the tight junctions to prevent the bacteria from entering the blood
C: Proliferate, allowing the blood vessel to enlarge
D: Secrete anti-microbial peptides
A: Increase their permeability,
allowing fluid and proteins to leak into tissue
Individuals or mice with defects in the biochemical pathways needed for loading peptides onto MHC molecules show greatly increased susceptibility to viral infections. Experiments examining the MHC molecules present on the surface of host cells in these individuals would show:
A: Normal number of MHC molecules
expressed on host cells, but no peptides bound to them
B: Very low levels of total MHC molecules expressed on the cell surface
C: Normal number of MHC molecules on the surface but all of them bound to self-peptides, not pathogen peptides
D: Very high levels of total MHC proteins expressed on the cell surface
B: Very low levels of total
MHC molecules expressed
on the cell surface
The process of somatic hypermutation takes place in the:
A: Dark zone of the germinal center
B: Light zone of the germinal center
C: T-B border
D: Subcapsular sinus of the lymph node
A: Dark zone of the germinal center
When a B cell gets signals 1 and 2 for the first time and is activated. It
has two options: 1) to form the primary focus or 2) migrate to follicle
to form the germinal center. Which statement is false:
A: Plasmablasts arise from primary focus
B: Plasma cells arise from germinal center
C: Plasmablasts can no longer proliferate
D:Plasma cells rapidly secrete antibodies
C: Plasmablasts can no longer proliferate
The process of somatic hypermutation of antibody V region sequences is initiated by the enzyme AID. AID is also involved in:
A: Transmembrane BCR → secreted antibod
B: Class switching of Ig
C: Naive T cell → effector T cell
D: Primary diversification of TCR and BCR
B: Class switching of Ig
I became this because I received IL-6, IL-23 and TGF-beta from an
APC. Now, I secrete my own cytokines, one of them being IL-22. IL-
22 can increase epithelial cell turnover, which can impair bacterial
growth. What cell am I:
A: Th1
B: Th17
C: Th2
D:CTL
B: Th17
Which of the following is/are effector functions of Th1?
D: Help activate CTLs
C: Induce alternatively
activated macrophages
B: Kill chronically infected
macrophages
A: Induce monocyte
differentiation in bone
marrow
A, B, D
You have three mice and in each, you injected either a virus, an extracellular
bacteria or an extracellular parasite to see which CD4+ T cell subset will dominate against each pathogen. Unfortunately, you forgot which mice are infected with which pathogen. You extract the T cell population from mouse 1 and see a large amount of phosphorylated STAT 1 and 4. What was this mouse most likely infected with:
D: STAT protein phosphorylation is
not an appropriate indicator of
different CD4+ T cell subsets
C: Extracellular parasite
B: Extracellular bacteria
A: Virus
A: Virus
