Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

B&L Unit 3 > Tumor Immunology (complete) > Flashcards

Tumor Immunology (complete) Flashcards

1
Q

What is the Immune Surveillance theory?

A

In 1959 Lewis Thomas theorized that:

  • T-cell mediate immune response evolved as a way to detect changes in the body’s own cell surface
  • Changes could be from damage or mutation
  • If an abnormal cell was detected, T cells would destroy it before it could multiply (become malignant)

According to this theory:
- Cancer is a failure of the adaptive immune system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Do data from immunosuppressed and immunodeficient patients support the Immune Surveillance theory? Why/why not?

A

YES!

  • Immunodeficient: those w/AIDS have ^ rate of Karposi sarcoma, Burkitt lymphoma, other tumors
  • Immunosuppressed: Organ xplant recipients have 25-100x ^ in tumors
  • Those w/ chemo: 14x ^ risk of secondary leukemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe tumor-associated antigens (TAA)

A

Ag on/in tumor cell

Often in a normal cell but it’s either overexpressed or abnormally expressed in tumor cells

Much lower quantities in normal cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe viral gene products (cancer)

A

Some tumors are caused by viruses (e.g. HPV-related cancers, Burkitt lymphoma [EBV])

Preventing virus is key

GO GET VACCINATED!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe mutant gene products (cancer)

A
  • Chemical/physical carcinogens lead to cellular transformation
  • Mutated proteins processed/presented to immune system
  • Mutations not always identical from pt to pt => immunotherapy designed against Ags may not be as generalizable as viral/normal gene products
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are oncofetal Ags?

A
  • Made in normal fetal tissue

- Not found in normal tissue in adults => can be re-expressed in tumor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are differentiation Ags?

A
  • Lineage specific tumor Ags (e.g. ovarian, breast cancers)
  • Most frequently identified TAA
  • Overexpressed in specific tumors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are clonal Ags?

A
  • Expressed uniquely on malignant clone
  • Eg: idiotype of surface Ig in B cell malignancies
  • Give hope for vaccine development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Define carcinoembryonic antigen (CEA)

A
  • A type of oncofetal Ag
  • Found in blood of pts w/ colon and other cancers
  • Was used as a screening tests
  • But there were too many false positives
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Discuss CEA’s usefulness in screening for, diagnosis, and follow-up of colon cancer

A
  • High false positives

However, useful for:

1) high suspicion of colon cancer
2) when that cancer has been removed => confirm complete excision
3) Warn of recurrent cancer after removal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the role of CTL cells in killing tumors cells. Include reference to the amount of MHC Class I expressed by tumor

A
  • CD8+ T cells
  • Can recognize TAA presented by MHC class I
  • Activated in lymph nodes (not tumor site) via APCs
  • After, undergo clonal expansion & acquire lytic abilities
  • Once activated => migrate to tumor
  • Kills tumor cells by inducing apoptosis
  • Also secrete IFN-gamma (attracts macros)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the role of NK cells in killing tumors cells. Include reference to the amount of MHC Class I expressed by tumor

A
  • usually called LGLs (large granular lymphocytes)
  • part of innate immunity
  • Recognize stressed-related markers on tumor cells w/ NK receptors
  • Down-regulated if the target cell expresses Class I MHC (thinks it’s CTL’s job to take care of it)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Discuss the roles of PD-1 and CTLA-4 in regulating T cell (especially CTL) acitivity

A

Both inactivate/downregulate CTL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Discuss the use of monoclonal blocking Abs against PD-1 and CTLA-4 to prevent CTL down-regulation in tumor patients

A

PD-1: monoAb binds/blocks CTL inactivation by tumors that express PD-1 ligands

CTLA-4: similar mechanism but different monoAg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the principles underlying Ab methods that might be used as treatments of tumors?

A
  • monoAbs => activate complement, tumor lysed/phagocytosed, ADCC
  • Also used to tag or poison tumor cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the principles underlying T cell methods that might be used as treatments of tumors?

A
  • Adoptive cell transfer therapy

not sure what else to say… sorry guys

17
Q

Describe a mechanism by which BCG treatment causes tumor regression

A
  • BCG is injected directly into tumor
  • Delayed-type hypersensitivity rxn starts => tumor cells are killed as innocent bystanders
  • Tx of choice in superficial bladder carcinoma
18
Q

Describe the nature and therapeutic use of tumor-infiltrating lymphocytes (TIL) in adoptive cellular transfer therapy

A

TIL: cells directly from tumor

  • Use pt’s immune system to destroy cancerous cells
  • T cells are expanded in culture using cytokines
  • Pt’s immune system is partially destroyed to make room for these add’l T cells
19
Q

What is immunoediting? What are the three stages of immunoediting?

A

Role of immune system in neoplastic development

1) Elimination
2) Equilibrium
3) Escape

20
Q

Describe the elimination stage of immunoediting

A

There are always new mutations in our body, but our immune system is constantly eliminating them

  • Malignant clone => recognized by innate & adaptive immune system => eliminated
  • DAMPs recognize metabolic abnormalities of tumor cells
  • DCs activate T cells => macros and CTLs infiltrate tumor

Process ends here if eradicated

21
Q

Describe the equilibrium stage of immunoediting

A
  • T/B cells infiltrate tumor => doesn’t destroy it (EQUILIBRIUM)
  • Analogous to latency
  • However, one’s immunity can drop for some reason => more mutations in tumor cells => reactivation
22
Q

Describe the escape stage of immunoediting

A

Tumor cells fight back!

  • Tumor-specific CTLs sometimes can’t fully kill the tumor
  • CTLs have >2 check point inhibitor surface receptors (CTLA-4 and PD-1) => if tumor cells interact with them => downregulation of cytotoxic activity
  • Tumor cells that escape CTLs become resistant to them => create an entire tumor of CTL-resistant cells

Either:

1) Suppress the immune system
2) Create decoys (become invisible)

B&L Unit 3 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions