15 Interactions in Adaptive Immunity Flashcards
What conditions the adaptive response to antigens?
The innate immune system
Which cells have memory?
T(TCR-MHC/peptide)
B (Ab-Ag)
NK (short memory only)
What cells “orchestrate” adaptive immunity?
T and B cells
T/F Most pathogens never activate the adaptive immune response?
True
How long does adaptive immunity take on first encounter? Second encounter?
- About 5 days to kick into gear
- Shorter
Over the time course of a virus infection, what cytokines are released in the first few days? What are the first immune CELLS that begin to attack? What cells then take over?
- IFN-alpha, IFN-Beta, TNF-alpha, IL-12
- NK’s
- T cells
How does a host cell sense virus nucleic acids?
- TLR 3,7,8,9
- RIG-I
- MDA5
Over the time course of a virus infection, in early-stage, what actions does the host take?
- 2’-5’-linked adenosine oligomers and kinase PKR
- Up MHC 1 expression, antigen presentation, and chemokines
- Activate DC’s, macrophages, NK’s
What is a T cell doubling time? How many cells can one naïve T cell produce in a week?
- 5-6 hours (about same as B cell germinal centers, fastest mammalian)
- 10,000
What third signal molecule is released to promote T cell survival during the proliferation phase?
-Bcl-2
What cytokines can provide signal 3?
IL-2,4,6,12,
IFN alpha or beta or gamma
What happens to an immune response without signal 3?
Some proliferation then dies off and produces tolerance (NOT immunity or memory)
About how long after initial infection does the immune contraction phase begin?
10 days (NOT based off clearance of infection)
Which cells expand more, CD 4 or CD 8?
CD8
T cells exhibit changes in receptors when they are naïve versus mature effectors. What are the only 2 receptors that are high in the mature stage?
- LFA-1, IFN-gamma (adhesion and effector) are high in mature, low in naive.
- All the rest are low in maturity and high in naive cells such as homing, chemokine, and cytokines.
Why are different receptors expressed in mature versus naive immune cells?
So they can leave secondary lymphoid organs & travel thru blood to inflamed tissues.
What actions do T cells take against a virus?
- CD4 & CD8 Produce IFN-gamma and TNF-alpha
- CD 4’s Amplify Ab and CD8 response
- CD8’s use perforin/granzyme and CD95(Fas)/CD95L(FasL) to kill
Which CD 4 T cell plays the most central role in host defense?
Th1
IL-2 is associated most with which cells?
-CD8s
IL-4 is associated most with which cells?
-Th2’s and B cells
T/F a vaccine is almost fully cleared by the body before the adaptive immune response comes into effect?
True
T/F Different people take different amounts of time to mount an immune response?
True
What happens to the adaptive immune response without Bim?
Contraction phase never occurs, and we are stuck with thousands of T cells. Bim induces apoptosis.
T/F second infection of the same pathogen mounts stronger and faster response than the first time?
True
What molecule presents on a T cell indicates it is exhausted? What cell contains this receptor?
- PD-1
- Antigen-presenting cells
Why does exhaustion occur? What is the difference between an exhausted cell and a normal one?
- To prevent host self-destruction
- It won’t release as much cytokines and its cytotoxicity is reduced
As T cells move from functional to exhausted to deleted, describe the levels of the following things:
-Antigen load, PD-1 expression, CD4 help, cytokine levels
- Low to High
- Low to High
- High to Low
- High to Low
What happens if PD-1/PD-L signaling is blocked?
T cell is re-invigorated
Signal 3 for T cell activation includes which 4 cytokines?
INF alpha, beta, gamma
IL 12
The FAS/FASL killing pathway is done by which cells?
CD 8 cells and helper T cells
What does BiM control?
CD 4 and CD 8 contraction
