Tumor Immunology Flashcards

1
Q

tumor antigens

A
mutated protein
normal cells do NOT express these antigens
not available during neg. selection: loaded onto MHC class I and presented to CTLs
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2
Q

tumor-associated antigens

A

un-mutated protein that is encoded in germ-line DNA of a cell whose level of expression has been dramatically altered by a neoplastic event
1. embryonic cells not available in T cell development
MHC class I presents to T cells
2. increased expression of normal self protein
increased density can lead to recognition by effector CTLs

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3
Q

proto-oncogenes

A

when mutated and activated: transform normal cell into a tumor cell

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4
Q

tumor suppressor genes

A

gene that encodes a protein that exerts control on cell growth rates

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5
Q

oncogenic viruses

A

express antigens that can serve as tumor antigens

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6
Q

Adaptations of tumors that enable them to avoid immune detection or effector function

A
  1. down-regulation of MHC class I

2. down regulation of T cell activation or effector function: expression of CTLA-4, TGF-beta, Fas-ligand, or PDL-1

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7
Q

bispecific Ab

A

recombinant with two arms
1. specific for CD3
2. specific for tumor antigen
recruits CD8 T cells to tumor
NOT a specific antigen activation: any T cell can be recruited
close contact causes degranulation rather than MHC and B7

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8
Q

CAR

A

chimeric antigen receptor
CTL with B cell receptor (heavy, light, and CD3 zeta chain)
CD3 zeta chain: causes intracellular signaling ot occur

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9
Q

carcinoma

A

cancer of epithelial cells

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10
Q

sarcoma

A

cancer of CT or non epithelial cells

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11
Q

leukemia

A

cancer of circulating cells of immune system

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12
Q

lymphomas

A

cancer of immune system involving solid lymphoid tumors

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13
Q

myelomas

A

cancer of immune system involving bone marrow

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14
Q

What is the effector mechanism our immune system sometimes has against tumor cells?

A

CTL

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15
Q

syngenic tumor transplantation

A

can transfer tumor from one mouse to another if they have matching MHC haplotypes
proves CTL resonse

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16
Q

allogenic tumor transplantation

A

can NOT transfer tumor between mice with mismatching MHC haplotypes
proves CTL response

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17
Q

HER2

A

oncogene: GF receptor

breast cancer

18
Q

B-RAF

A

oncogene: intracellular signal

melanoma

19
Q

MYC

A

oncogene: TF

neuroblastoma

20
Q

RAS

A

oncogene: intracellular signal

colorectal cancer

21
Q

B-catenin

A

oncogene: intracellular signal

various cancers

22
Q

VEGF

A

oncogene: angiogenesis

colorectal cancer

23
Q

APC

A

tumor suppressor: scaffolding protein

colorectal cancer

24
Q

TP53

A

tumor suppressor: regulates cell division

lung cancer

25
Q

RB

A

tumor suppressor: regulates cell division

melanoma

26
Q

CDKN2A

A

tumor suppressor: regulates cell division

melanoma

27
Q

p53

A

tumor suppressor: regulates cell division

various cancers

28
Q

MAGE, GAGE, BAGE, RAGE

A

target of CTL-mediated killing when expressed outside of testes (immunoprivileged: not available during T cell development)

29
Q

oncofetal antigens

A

genes normally only expressed during embryonic development that are expressed in a tumor
NOT available for B and T cell negative selection

30
Q

MUC-1

A

mucin found on many breast carcinomas

tumor specific carbohydrate and peptide epitopes: induces both antibody and T cell response

31
Q

examples of abnormal forms or elevated levels of glycolipids and glycoproteins that can be diagnostic for cancers

A

gangliosides, blood group antigens, mucins

32
Q

CA-125

A

mucin found in ovarian carcinomas

33
Q

CA-19-9

A

mucin found in ovarian carcinomas

34
Q

cell type specific differentiation antigens

A

normally expressed by a cell at different stages of differentiation of that cell type; tumor cell will typically express antigen that were being expressed by the cell when neoplastic event occurred
ex: CD20, CD1, CD3, CD4, CD8
normally recognized proteins that were available during thymic selection: no T cells specific for them

35
Q

TGF-beta

A

immunosuppressive environment around the tumor

36
Q

Fas-ligand

A

engage with Fas on immune cells and induce apoptosis

37
Q

PD-L1

A

ligand for PD-1 on effector T cells
down regulation of function
protection from CTLs if expressed

38
Q

How can tumors evade the immune system?

A
  1. defects in expression of MHC class I: Evade CTL but increase NK killing
  2. TGF-beta
  3. Fas-Ligand
  4. PD-L1
  5. CTLA-4
39
Q

conjugated Ab

A

tumor-antigen specific MAb delivers toxin, drug or radio nucleotide to tumor

40
Q

CTLA-4

A

on naive T cells and Tregs
binds B7, preventing CD28 from binding
causes T reg to secrete TGF-beta, preventing T cell activation

41
Q

blinatumomab

A

biphasic Ab
anti-CD3 arm (T cell) and anti-C19 arm (tumor antigen)
Tx: B cell lymphoma