BRAINSCAPE1
BCMB 406A Exam with complete
solutions latest version
Purpose of Lab 2 - CORRECT ANSWER-Characterize mouse breast cancer cell lines
What does an immune response require? What is this requirement dependent on? -
CORRECT ANSWER-- Requires the generation/expansion of CTLs
- Dependent on Ag processing and presentation of peptides
Exogenous Antigen Recognition - CORRECT ANSWER-- Exogenous Ags are
processed and presented in MHC class II molecules to CD4+ T cells
- Extracellular pathogens
Endogenous Ag Recognition - CORRECT ANSWER-- Endogenous Ags are recognized
by CD8+ T cells via MHC class I molecules
- Intracellular pathogens/malignant cells
Where are MHC Class I and Class II molecules expressed? - CORRECT ANSWER--
MHC class I: every nucleated cell
- MHC class II: lymphocytes & APCs
Antigen Presenting Cell (APC) - CORRECT ANSWER-- Internalizes and displays Ag
complexed with MHC on cell surface to CD4+ and CD8+ T cells
1) Cross Presentation
2) Cross Priming - what is it necessary for? - CORRECT ANSWER-1) the ability of
APCs to take up, process, and present extracellular Ag with MHC Class I to CD8+ cells
2) the stimulation of CD8+ T cells by cross presentation, necessary for immunity against
tumors/viruses that don't infect APCs
Proteasome - CORRECT ANSWER-Degrades/processes intracellular proteins and Ag
to peptide epitopes
BRAINSCAPE1
, BRAINSCAPE1
CD8+ T Cells - CORRECT ANSWER-CTLs, capable of inducing death of tumor cells or
somatic cells infected with viruses or pathogens
T Cell Receptor - what must it recognize? - CORRECT ANSWER-Complex on T cell
surfaces that recognizes peptide in context of MHC molecules and associates with CD3
- It must recognize both self MHC class I molecule and the peptide epitope in MHC
groove
Ag processing for MHC Class I presentation - pathway - CORRECT ANSWER-1)
Peptide generated by proteasome
2) peptides transported into the ER by TAP
3) Peptides bound to empty MHC complex
4) Peptide/MHC complex exits ER
5) Complex is glycosylated in the Golgi
6) Complex is transported to cell surface
How is a CD8+ T cell activated? - CORRECT ANSWER-- Recognition of the peptide in
the MHC Class I
- IL-2 that is secreted upon CD4+ T cells binding the APC
Tumor Escape Mechanisms - CORRECT ANSWER-1) Lack of danger signals
2) Physical exclusion of T cells from tumor
3) Loss of tumor Ag
4) Downregulation of MHC Class I
5) Expression of Immunosuppressive cytokines
6) Recruitment/differentiation of immunosuppressive populations
7) Induction of T cell anergy
8) Resistance to apoptosis
9) Expression of death receptors that trigger apoptosis of T cells
How does the tumor "escape" using lack of danger signals? - CORRECT ANSWER-
Tumor is "self" and tolerated because autoreactive T cells aren't present
How does the tumor "lose" its Ag expression? - CORRECT ANSWER-- Selection of
cells with low/no Ag expression
- Mutations that prevent T cell recognition
What are tumors commonly characterized by? - CORRECT ANSWER-- Decreased
tumor Ag
- Deficiencies in Ag processing and presentation
What immunosuppressive cytokines are expressed by tumor cells? - CORRECT
ANSWER-1) TGFB - inhibits Ag presentation, T-cell prolif., NK cell cytotoxivity, and
activates T regulatory cells
2) VEGF - inhibits T cell activation
3) IL-10: promotes differentiation into TH2 cells
BRAINSCAPE1
, BRAINSCAPE1
Anergy - CORRECT ANSWER-The absence of normal immune response to an Ag
How does a tumor cell resist apoptosis - CORRECT ANSWER-1) expression of anti-
apoptotic molecules
2) alterations in pro-apoptotic molecules
Immunoediting process - CORRECT ANSWER-1) Normal tissue --> Transformed
2) Elimination - CTKS recognize and eliminate tumor cells
3) Equilibrium - Tumor dormancy and editing
4) Escape - Tumor growth and proliferation
What special characteristic of tumors allow it to escape the CTKs (immunoediting
process) - CORRECT ANSWER-Heterogeneity of the tumor
Inflammatory macrophage functions - CORRECT ANSWER-- Defense against bacteria
- Tumor suppression
- Immuno-stimulation
Immunosuppressive tumor-associated macrophage functions - CORRECT ANSWER--
Tissue repair and angiogenesis
- Tumor promotion
- Down-regulation of inflammatory macrophages and adaptive immunity
Immature Myeloid Cells - CORRECT ANSWER--Inhibit Ag specific T cells via direct cell-
cell contact
--> Tumor growth due to inhibited response
1) Immature Dendritic Cells
2) Mature Dendritic Cells - CORRECT ANSWER-1) Take up the tumor cell Ags and
present them in MHC Class I molecules
- Inhibit Mature dendritic cells
- Lead to T cell anergy --> tumor growth
2) Cannot stimulate an anti-tumor response when inhibits/decreased by iDCs
IFN-gamma - CORRECT ANSWER-- Secreted by CD4+/CD8+ T cells, DCs, NK cells
- Antiviral, immunoregulatory, and anti-tumor properties
- Up-regulates expression of components in the MHC Class I presentation pathway
--> can determine if defect is structural or regulatory
Will IFN-gamma restore a:
1) regulatory defect
2) structural defect - CORRECT ANSWER-1) Restores Ag processing and presentation
2) Ag processing/presentation not restored
Immunotherapy - CORRECT ANSWER-- Using the immune system/components of it to
fight cancer
- Requires immunological characterization of tumors
BRAINSCAPE1
BCMB 406A Exam with complete
solutions latest version
Purpose of Lab 2 - CORRECT ANSWER-Characterize mouse breast cancer cell lines
What does an immune response require? What is this requirement dependent on? -
CORRECT ANSWER-- Requires the generation/expansion of CTLs
- Dependent on Ag processing and presentation of peptides
Exogenous Antigen Recognition - CORRECT ANSWER-- Exogenous Ags are
processed and presented in MHC class II molecules to CD4+ T cells
- Extracellular pathogens
Endogenous Ag Recognition - CORRECT ANSWER-- Endogenous Ags are recognized
by CD8+ T cells via MHC class I molecules
- Intracellular pathogens/malignant cells
Where are MHC Class I and Class II molecules expressed? - CORRECT ANSWER--
MHC class I: every nucleated cell
- MHC class II: lymphocytes & APCs
Antigen Presenting Cell (APC) - CORRECT ANSWER-- Internalizes and displays Ag
complexed with MHC on cell surface to CD4+ and CD8+ T cells
1) Cross Presentation
2) Cross Priming - what is it necessary for? - CORRECT ANSWER-1) the ability of
APCs to take up, process, and present extracellular Ag with MHC Class I to CD8+ cells
2) the stimulation of CD8+ T cells by cross presentation, necessary for immunity against
tumors/viruses that don't infect APCs
Proteasome - CORRECT ANSWER-Degrades/processes intracellular proteins and Ag
to peptide epitopes
BRAINSCAPE1
, BRAINSCAPE1
CD8+ T Cells - CORRECT ANSWER-CTLs, capable of inducing death of tumor cells or
somatic cells infected with viruses or pathogens
T Cell Receptor - what must it recognize? - CORRECT ANSWER-Complex on T cell
surfaces that recognizes peptide in context of MHC molecules and associates with CD3
- It must recognize both self MHC class I molecule and the peptide epitope in MHC
groove
Ag processing for MHC Class I presentation - pathway - CORRECT ANSWER-1)
Peptide generated by proteasome
2) peptides transported into the ER by TAP
3) Peptides bound to empty MHC complex
4) Peptide/MHC complex exits ER
5) Complex is glycosylated in the Golgi
6) Complex is transported to cell surface
How is a CD8+ T cell activated? - CORRECT ANSWER-- Recognition of the peptide in
the MHC Class I
- IL-2 that is secreted upon CD4+ T cells binding the APC
Tumor Escape Mechanisms - CORRECT ANSWER-1) Lack of danger signals
2) Physical exclusion of T cells from tumor
3) Loss of tumor Ag
4) Downregulation of MHC Class I
5) Expression of Immunosuppressive cytokines
6) Recruitment/differentiation of immunosuppressive populations
7) Induction of T cell anergy
8) Resistance to apoptosis
9) Expression of death receptors that trigger apoptosis of T cells
How does the tumor "escape" using lack of danger signals? - CORRECT ANSWER-
Tumor is "self" and tolerated because autoreactive T cells aren't present
How does the tumor "lose" its Ag expression? - CORRECT ANSWER-- Selection of
cells with low/no Ag expression
- Mutations that prevent T cell recognition
What are tumors commonly characterized by? - CORRECT ANSWER-- Decreased
tumor Ag
- Deficiencies in Ag processing and presentation
What immunosuppressive cytokines are expressed by tumor cells? - CORRECT
ANSWER-1) TGFB - inhibits Ag presentation, T-cell prolif., NK cell cytotoxivity, and
activates T regulatory cells
2) VEGF - inhibits T cell activation
3) IL-10: promotes differentiation into TH2 cells
BRAINSCAPE1
, BRAINSCAPE1
Anergy - CORRECT ANSWER-The absence of normal immune response to an Ag
How does a tumor cell resist apoptosis - CORRECT ANSWER-1) expression of anti-
apoptotic molecules
2) alterations in pro-apoptotic molecules
Immunoediting process - CORRECT ANSWER-1) Normal tissue --> Transformed
2) Elimination - CTKS recognize and eliminate tumor cells
3) Equilibrium - Tumor dormancy and editing
4) Escape - Tumor growth and proliferation
What special characteristic of tumors allow it to escape the CTKs (immunoediting
process) - CORRECT ANSWER-Heterogeneity of the tumor
Inflammatory macrophage functions - CORRECT ANSWER-- Defense against bacteria
- Tumor suppression
- Immuno-stimulation
Immunosuppressive tumor-associated macrophage functions - CORRECT ANSWER--
Tissue repair and angiogenesis
- Tumor promotion
- Down-regulation of inflammatory macrophages and adaptive immunity
Immature Myeloid Cells - CORRECT ANSWER--Inhibit Ag specific T cells via direct cell-
cell contact
--> Tumor growth due to inhibited response
1) Immature Dendritic Cells
2) Mature Dendritic Cells - CORRECT ANSWER-1) Take up the tumor cell Ags and
present them in MHC Class I molecules
- Inhibit Mature dendritic cells
- Lead to T cell anergy --> tumor growth
2) Cannot stimulate an anti-tumor response when inhibits/decreased by iDCs
IFN-gamma - CORRECT ANSWER-- Secreted by CD4+/CD8+ T cells, DCs, NK cells
- Antiviral, immunoregulatory, and anti-tumor properties
- Up-regulates expression of components in the MHC Class I presentation pathway
--> can determine if defect is structural or regulatory
Will IFN-gamma restore a:
1) regulatory defect
2) structural defect - CORRECT ANSWER-1) Restores Ag processing and presentation
2) Ag processing/presentation not restored
Immunotherapy - CORRECT ANSWER-- Using the immune system/components of it to
fight cancer
- Requires immunological characterization of tumors
BRAINSCAPE1
