Tumor Immunology

Question 1

Carcinoma

Answer 1

epithelial cells

most common cancers

Question 2

Sarcomas

Answer 2

muscle cells, fat cells or fibroblasts

Question 3

lymphoma

Answer 3

solid tumors of lymphoid tissue

Question 4

leukemias

Answer 4

lymphocytes and other hematopoetic cells

Question 5

benign tumors

Answer 5

slow growth rate
somewhat differentiated cells
usually encapsulated, so they don’t spread
not normally fatal unless they are in specific spots

Question 6

malignant tumors

Answer 6

undifferentiated cells
readily metastasize
fatal if untreated

Question 7

TSAs

Answer 7

antigens unique to a particular tumor and not present on normal cells types
very common in animals, but not often seen in humans
good target for immune response

Question 8

TAAs

Answer 8

antigens shared by different tumors, also found on normal tissues
can be useful for diagnosis, but not so much for treatment

Question 9

oncofetal antigens

Answer 9

expressed on fetal, but not adult tissues

Question 10

alpha fetal proteins (AFP)

Answer 10

produced by certain liver cancers

Question 11

carcinoembryonic antigen (CEA)

Answer 11

increased in colon cancer and smokers

Question 12

oncogenic viral antigens

Answer 12

happens with some RNA/DNA viruses

makes tumors easy for immune system to deal with because they are seen as foreign

Question 13

Differentation antigens

Answer 13

tissue specific antigens

good for diagnosis, but not so much for treatment

Question 14

antibodies

Answer 14

super weak sauce
don’t help
some times actually hurt

Question 15

CTLs

Answer 15

most effective against virus induced tumors

Question 16

NK cells

Answer 16

help against tumors of hematopoetic origin and those that are virus induced
activating signal is a down-regulation of class I MHC
their effect is enhanced by interferons, TNF-alpha, and IL-2

Question 17

Lymphokine-activated killer (LAK) cells

Answer 17

enhanced killing of various tumors and broadened tumor recognition capability

Question 18

Macrophage

Answer 18

kill tumor cells by ADCC or by release of TNF-alpha

Question 19

TNF

Answer 19

can directly lyse tumor cells possibly by producing free radicals or by causing hemorrhagic necrosis of the tumor blood vessels

Question 20

Examples of tumor evasion strategies

Answer 20

don’t express MHC proteins
anti-tumor antibodies may act as blocking factors
antigens shed by tumor cells bind to cell surface receptors
tumor antigens masked by mucopolysacchardes
tumor releases immunosuppressive suvstances
creating an immunoprivileged site by encasing themselves in collagen and fibrin

Question 21

Treatment by antibodies to surface immunoglobulin of B cell lymphomas

Answer 21

cell lysis by ADCC or complement required to decrease tumor burden
outgrowth of tumor cell mutants are a problem

Question 22

Herceptin

Answer 22

targets HER-2/neu growth factor receptor

blocks receptor/ligand interaction

Question 23

Immunoconjugates

Answer 23

antibodies coupled to a toxic substance
conjugate must be endocytoses
F(ab’)2 fragments (no Fc regions) used to avoid non-specific binding

Question 24

Bi-specific antiodies

Answer 24

genetically-engineered antibodies that recognize tumor antigens and immune system cells

Question 25

Advantages of tumor immunotherapy advantages

Answer 25

specifically tailor a response to the tumor
fewer side effects than nonspecific therapies
more effective against tumor metastasis

Question 26

Tumor vaccines

Answer 26

vaccinate with tumor cells treated to increase immunogenicity or dendritic cells that have been loaded with tumor antigens
ex) melanoma, hep B vaccine

Question 27

LAK cell theraoy

Answer 27

peripheral blood NK cells cultured in high does IL-2 to make LAK cells
LAK cells re-infused into patient, and the LAK cells kill the tumor
most success with renal cell carcinoma and malignant melanoma

Question 28

TIL therapy

Answer 28

leukocytes from solid tumors cultured with IL-2 and given to patient
LAK cells and tumor CTLs are grown up in this technique

Question 29

Cytokine therapy

Answer 29

IL-2 given to patients to generate LAK cells and activate CTLs
have a lot of tumor regression BUT crazy side effects (shock and death)

Question 30

Positive effects of IFN-alpha

Answer 30

tumor antiproliferative effects
increased NK cell activity
increased class I MHC expression on tumor cells