18. Tumor Immunology and Immunotherapy

Question 1

What is the relationship between immune surveillance and immunoediting?

Answer 1

Tumor immunoediting involves the elimination of tumor cells by immune surveillance

Question 2

What would an increasing level of a tumor associated antigen indicate about a cancer patient undergoing chemotherapy?

Answer 2

An increasing level would indicate that the chemotherapy is not successful/effective.

Question 3

What type(s) of tumors is Alpha-1-Fetoprotein (AFP) associated with?

Answer 3

Primarily testicular and hepatocellular

Question 4

What type(s) of tumors is CA 125 associated with?

Answer 4

primarily ovarian

Question 5

What cells are involved in nonspecific immune responses to tumor cells?

Answer 5

• NK cells
• LAK cells
• Macrophages

Question 6

What cells are involved in specific immune responses to tumor cells?

Answer 6

• CTL-mediated (involves APC, T helper, and CTL)

- Antibody dependent cell-mediated (involves NK cell and macrophages)

Question 7

Which cytokine is released by macrophages in the nonspecific response to tumors, and how does it function?

Answer 7

• lysosomal enzymes, reactive oxygen species, and TNF-alpha are released from macrophage.
• TNF-alpha has cytotoxic effects on tumor cells

Question 8

What role do antibodies play in the immune response to tumor cells?

Answer 8

Antibody Dependent Cell-Mediated Cytotoxicity (ADCC)

• involves antibody to tumor Ag
• Ab -> Ag, FcR on NK or macrophage -> Fc portion of Ab -> release of enzymes -> tumor cell destroyed

Question 9

What are 4 ways in which a tumor cell can evade the immune response?

Answer 9

1. Alteration of tumor antigens or other surface markers
2. Antigen masking
3. APC may fail to adequately present tumor antigens to T cells
4. Suppression of the immune response

Question 10

What cytokines have been used to treat tumors and what are their modes of action?

Answer 10

1. Interferons alpha, beta, and gamma
   Mechanism: Destruction of virus-infected cells, enhancement of macrophage and NK function, increase of MHC antigen expression
2. IL-2
   Mechanism: stimulates proliferation of activated T helper cells, induces maturation of CTL

Question 11

Which cytokine is used to generate LAK cells for use in adaptive immunotherapy?

Answer 11

Incubation of tumor-infiltrating cells (TIL) or lymphocytes from peripheral blood with IL-2