Tumor Immunology

Question 1

What are five pieces of evidence that the immune system recognizes tumors?

Answer 1

Spontaneous regression of certain tumors

Infiltration of tumors with immune cells

Tumor-specific antibodies circulate

Tumors tend to occur most in young/old

Tumors often arise in immunosuppressed patients

Question 2

What is the relationship between number/type of T cells in a tumor and survival?

Answer 2

If there are a lot of T cells and they are Th or cytotoxic T cells, then there is a higher chance or survival

If there are only a few T cells, or the T cells are Tregs, then there is a lower chance of survival

Question 3

What type of immunity do tumor antigens stimulate?

Answer 3

Both CMI and humoral immunity

The same antigen, different epitopes, elicit both T cells and antibody formation

E.g. tyrosinase, CEA, and MAGE

Question 4

What are tumor-specific antigens?

Answer 4

Found only on tumor cells

Mutation in normal cellular proteins

Oncogenic viral antigen

Question 5

What are tumor-associated antigens?

Answer 5

Found both on tumor and normal cells

Re-expressed embryonic antigens

Over-expressed low abundance self-protein

Question 6

What is the major immunity mechanism involved in killing cancer cells?

Answer 6

ADCC

Question 7

How do macrophages kill tumor cells?

Answer 7

Can phagocytize and kill tumor cells via nitric oxide

Selectively kill tumor cells

Question 8

What two things do tumors rely on to successfully survive?

Answer 8

Neovascularixation

Immune evastion

Question 9

What three general mechanisms do tumors have to evade the immune system?

Answer 9

Down regulate MHC I antigens

Down regulate tumor associated antigens

Release suppressive factors (TGF-B, IL-10) or induce the host to release suppressive factors or tumors attract and stimulate the generation of Tregs and MDSCs

Question 10

What two principle types of cells are involved in the evasion of anti-tumor immune response?

Answer 10

Tregs

Myeloid Derived Suppressor Cells