MICR 3230 - FINAL EXAM REVIEW
QUESTIONS AND ALL CORRECT
ANSWERS 2026/2027 UPDATED.
A stem cell is exposed to notch1, what is the outcome of this? - Answer Commitment to the T-
cell lineage
A DN T-cell which lacks CD44 will lack what? - Answer Adhesion molecules
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
(T/F) cytokines are long lived once in circulation - Answer false
A dendritic cell (DC) presenting only MHC class II encounters a naive CD8+ cell. What is a
reasonable outcome? - Answer No interaction will occur
What happens to T-cells which fail to meet selection criteria? - Answer Apoptosis
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
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
why are the same cytokines produced by multiple cell types? - Answer redundancy
how do T-regulatory cells negatively regulate the immune response? - Answer - suppress
autoreactive immune responses
- express surface CD4 and CD25
- express FoxP3
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
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)
What happens with disruption of MHC class III? - Answer susceptibility to infectious diseases
increases + autoimmune diseases can occur (e.g. Crohn's disease)
List 5 barrier organs of immunity: - Answer 1. skin
2. intestinal tract
3. respiratory tract
4. urogenital tracts
5. mouth
Barrier organs provide a barrier for what 2 things? - Answer microbiota and pathogens
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
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
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
- effectors: eosinophil/macrophage, B cells that produce IgG4 and IgE subclasses
- worm expulsion, tissue repair, mucus secretion from epithelia
What are the pathogens, sensing cells, cytokines produced, cells that organize the responses,
effector cells and their responses in the Type 3 immune response? - Answer - pathogens:
worms, allergens, venoms
- sensors: PRRs on macrophage DCs
- cytokines: IL-1B, Il-23 ---> IL-17, IL-22, IL-21
- ILC3, Th17, NK, CTL, and other T-cells
- effectors: eosinophil/macrophage, B cells that IgG subclasses
- killing of pathogens, tight junction enhancement, increased antimicrobial peptide production,
proliferation of epithelia
What type of immunity?
Cells that recognize and kill or engulf pathogen =
Soluble proteins for labeling and destruction of invaders: - Answer cell-mediated
humoral
PRRs vs. DAMPS - Answer PPRs: encoded in genomic DNA and always expressed, bind to
PAMPs
QUESTIONS AND ALL CORRECT
ANSWERS 2026/2027 UPDATED.
A stem cell is exposed to notch1, what is the outcome of this? - Answer Commitment to the T-
cell lineage
A DN T-cell which lacks CD44 will lack what? - Answer Adhesion molecules
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
(T/F) cytokines are long lived once in circulation - Answer false
A dendritic cell (DC) presenting only MHC class II encounters a naive CD8+ cell. What is a
reasonable outcome? - Answer No interaction will occur
What happens to T-cells which fail to meet selection criteria? - Answer Apoptosis
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
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
why are the same cytokines produced by multiple cell types? - Answer redundancy
how do T-regulatory cells negatively regulate the immune response? - Answer - suppress
autoreactive immune responses
- express surface CD4 and CD25
- express FoxP3
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
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)
What happens with disruption of MHC class III? - Answer susceptibility to infectious diseases
increases + autoimmune diseases can occur (e.g. Crohn's disease)
List 5 barrier organs of immunity: - Answer 1. skin
2. intestinal tract
3. respiratory tract
4. urogenital tracts
5. mouth
Barrier organs provide a barrier for what 2 things? - Answer microbiota and pathogens
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
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
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
- effectors: eosinophil/macrophage, B cells that produce IgG4 and IgE subclasses
- worm expulsion, tissue repair, mucus secretion from epithelia
What are the pathogens, sensing cells, cytokines produced, cells that organize the responses,
effector cells and their responses in the Type 3 immune response? - Answer - pathogens:
worms, allergens, venoms
- sensors: PRRs on macrophage DCs
- cytokines: IL-1B, Il-23 ---> IL-17, IL-22, IL-21
- ILC3, Th17, NK, CTL, and other T-cells
- effectors: eosinophil/macrophage, B cells that IgG subclasses
- killing of pathogens, tight junction enhancement, increased antimicrobial peptide production,
proliferation of epithelia
What type of immunity?
Cells that recognize and kill or engulf pathogen =
Soluble proteins for labeling and destruction of invaders: - Answer cell-mediated
humoral
PRRs vs. DAMPS - Answer PPRs: encoded in genomic DNA and always expressed, bind to
PAMPs
