MICR 3230 - FINAL EXAM REVIEW University of Guelph | UPDATED Questions with 100% Verified Answers

MICR 3230 - FINAL EXAM REVIEW University of Guelph |
UPDATED Questions with 100% Verified Answers

Question:
A stem cell is exposed to notch1, what is the outcome of this?

Answer:
Commitment to the T-cell lineage


Question:
A DN T-cell which lacks CD44 will lack what?

Answer:
Adhesion molecules


Question:
What model proposed for differentiation of T-cells into CD4
or CD8 relies on random downregualtion of either the CD4 or
CD8 receptor?

Answer:
the stochastic model


Question:
(T/F) cytokines are long lived once in circulation

Answer:
false


Question:
A dendritic cell (DC) presenting only MHC class II encounters
a naive CD8+ cell. What is a reasonable outcome?

Answer:
No interaction will occur


Question:
What happens to T-cells which fail to meet selection criteria?

, Answer:
Apoptosis


Question:
A host cell that lacks the ability to produce MHC molecules is
exposed to a NK cell. WHat is the outcome of the host cell?

Answer:
THe host cell is killed by the NK cell


Question:
A CD8+ T-cell recognizes a foreign cell and is going to destroy
it. How long after this recognition will it take for the foreign
cell to have undergone apoptosis from the time of
recognition?

Answer:
~1 hour


Question:
why are the same cytokines produced by multiple cell types?

Answer:
redundancy


Question:
how do T-regulatory cells negatively regulate the immune
response?

Answer:
- suppress autoreactive immune responses
- express surface CD4 and CD25
- express FoxP3


Question:
What are the instructive, stochastic, and kinetic signaling
models?

Answer:

,Instructive: TCR/CD4 and TCR/CD8 co-engagement generate unique signals to initiate
distinct developmental programs
CD8 + TCR engagement -> CD4-8+ T cell
CD4 + TCR engagement -> CD4+8- T cell)
Stochastic: positively selected thymocyte randomly down-regulates
CD4 -> able to/not able to bind Ag + MHC class I
CD8 ->able to/not able to bind Ag + MHC class II
Kinetic signaling: thymocytes
(1) commit to CD4+ T cell lineage if they receive a continuous signal in response to
TCR/coreceptor engagement
(2) commit to CD8+ if the TCR signal is interrupted


Question:
What are some immune functions of MHC class III?

Answer:
(1) encodes complement components C4, C2, Factor B (2) produces inflammatory
cytokines (e.g. tumor necrosis factor)


Question:
What happens with disruption of MHC class III?

Answer:
susceptibility to infectious diseases increases + autoimmune diseases can occur (e.g.
Crohn's disease)


Question:
List 5 barrier organs of immunity:

Answer:
1. skin
2. intestinal tract
3. respiratory tract
4. urogenital tracts
5. mouth


Question:

, Barrier organs provide a barrier for what 2 things?

Answer:
microbiota and pathogens


Question:
List 3 main features of barrier organs:

Answer:
1. lined with epithelial cells
2. interact with immune cells
3. help provide balance between tolerance and inflammation


Question:
What are the pathogens, sensing cells, cytokines produced,
cells that organize the responses, effector cells and their
responses in the Type 1 immune response?

Answer:
- pathogens: viruses, bacteria, protozoa
- sensors: PRRs on macrophage DCs
- cytokines: IL-12, IL-18 ---> IFN-y, IL-21
- ILC1, Th1, NK, CTL, Tfh and other T-cells
- effectors: granulocyte/macophage, B cells that produce IgG subclasses
- killing of pathogens, tight junction enhancement, increased antimicrobial peptide
production, proliferation of epithelia


Question:
What are the pathogens, sensing cells, cytokines produced,
cells that organize the responses, effector cells and their
responses in the Type 2 immune response?

Answer:
- pathogens: worms, allergens, venoms
- sensors: PRRs on epithelia
- cytokines: TSLP, Il-4, IL-24, IL-33 ---> Il-4, Il-5, Il-13, AREG, Il-9l IL21
- ILC2, Th2, Th9 and other T-cells