Cellular therapies

Question 1

What is adoptive T-cell therapy?

Answer 1

Isolation of T-cells, expansion & transfer back to patients

Question 2

Which T-cell types are being explored for adoptive T-cell therapy?

Answer 2

1. Tumour-infiltrating lymphocytes (TILs)
2. Gene-engineered T-cells

Question 3

What is the strategy of adoptive T-cell therapy using TILs?

Answer 3

Ex vivo expansion of naturally occuring TILs isolated from the tumour

Question 4

Where are T-cells for genetic engineering isolated?

Answer 4

Patient peripheral blood

Question 5

What is usually changed in engineered T-cell therapy?

Answer 5

Genetically engineered receptor to make the T-cells (more) tumour-specific

Question 6

Which two options are there for T-cell receptor engineering?

Answer 6

1. CAR T-cell receptor
2. TCR-cells

Question 7

What is a CAR T-cell receptor?

Answer 7

Chimeric antigen receptor

Question 8

Do CAR or TCR T-cells have higher antigen affinity? Why?

Answer 8

CAR T-cells have higher antigen affinity due to its antigen-recognizing domain being an antibody

Question 9

What are the characteristics of TCR T-cells? (3)

Answer 9

1. Recognition of peptides in MHC
2. Access to intra- en extracellular peptides
3. Low-to-intermediate affinity binding

Question 10

What are characteristics of CAR T-cells?

Answer 10

1. Recognition of peptides independent of MHC
2. Access to extracellular peptides only
3. High affinity binding

Question 11

What is the advantage of the MHC-independence of CAR T-cells?

Answer 11

Allows these cells to circumvent downregulation of MHC, which often happens in tumours

Question 12

What are the goals of the field of adoptive T-cell therapy? (2)

Answer 12

1. Expand the number of target antigens to be able to treat (nearly) all types of tumours
2. Increase longevity of T-cells to induce long-term regression

Question 13

What are requirements for TCR/CAR therapy targets? (5)

Answer 13

1. Not expressed in healthy tissues
2. Abundantly expressed in tumour
3. Preferably expressed in multiple tumour types
4. Preferable expressed shared between patients
5. Immunogenic

Question 14

What are the groups of suitable TCR/CAR therapy antigens? (3)

Answer 14

1. Target antigens related to oncogenesis
2. Antigens related to immune evasion in tumours
3. New antigens related to HLA mis-match

Question 15

What are target antigens related to oncogenesis? (5)

Answer 15

1. Differentiation antigens
2. Over-expressed antigens
3. Cancer germline antigens
4. Onco-viral antigens
5. Cancer neoantigens

Question 16

What is the downside of using differentiation antigens as targets for TCR/CAR therapy?

Answer 16

They are ovexpressed in tumours, but not completely absent in healthy cells

Question 17

What is the downside of using over-expressed tumour-associated antigens as targets for TCR/CAR therapy?

Answer 17

They are highly selective, but not completely selective for tumour cells

Question 18

What are the advantages of using cancer germline antigens as targets for TCR/CAR therapy? (2)

Answer 18

1. They are often not expressed in mature tissues -> high tumour-specificity
2. Shared by tumour types & among patients

Question 19

What is the advantage and what is the disadvantage of using oncoviral antigens as targets for TCR/CAR therapy?

Answer 19

Advantage: highly tumour-specific
Disadvantage: only found in tumours derived from viral infections

Question 20

What are cancer neoantigens?

Answer 20

Non-physiological antigens, resulting from gene mutations/abberations in tumour cells

Question 21

What are the advantages of cancer neoantigens as targets for TCR/CAR therapy? (2)

Answer 21

1. Exclusively expressed by tumour cells
2. Can be shared between multiple tumour sites, as they often occur in the same genes

Question 22

What is the disadvantage of cancer neoantigens as targets for TCR/CAR therapy?

Answer 22

They are not necessarily shared between many patients

Question 23

What is the process of antigen discovery for TCR/CAR therapy? (7)

Answer 23

1. In silico prediction of antigens from databases
2. Checking absence of expression in healthy tissues using mRNA & protein expression assays
3. Checking expression of antigen in target tumour tissue
4. Antigen epitope selection using in silico prediction
5. Confirmation of selected epitopes using immunopeptidomics
6. Exclusion of potential cross-reactivity using expitope screen
7. Selecting of most promising epitopes according to HLA avidity

Question 24

What is a disadvantage of TCR T-cell therapy?

Answer 24

The original TCR is not eliminated

Question 25

On which parameters do TCR T-cells need to be tested? (3)

Answer 25

1. Sensitivity 2. Specificity 3. Efficacy

Question 26

How can sensitivity of TCR T-cells be tested?

Answer 26

Co-culture of TCR T-cells with target tumour cell line expressing target antigen

Question 27

How can specificity of TCR T-cells be tested?

Answer 27

Co-culturing TCR T-cells with various tissues & cell lines to make sure that there is no cross-reactivity

Question 28

Why is it necessary to increase longevity of TCR T-cells?

Answer 28

Patients can relapse due to short persistence of TCR T-cells in blood

Question 29

True or false: TCR T-cells do not proliferate after infusion, explaining their relatively short effect

Answer 29

False; TCR T-cells do show proliferation in vivo, but are unable to keep proliferating at a level high enough to induce long-term regression

Question 30

What are modifications that can be made to TCR T-cells to increase their longevity? (4)

Answer 30

1. Co-stimulatory TCRs/CARs 2. Chemokine/cytokine receptors 3. Inducible mediators 4. Gene deletion/silencing

Question 31

How can co-stimulatory TCRs/CARs increase adoptive T-cell longevity?

Answer 31

The tumour micro-environment in which these T-cells operate lacks effective costimulation. By engineering costimulatory domains to the intracellular domain of the TCR, TCR activation automatically ensures the desired level of costimulation.

Question 32

What are the in vivo results of engineered TCRs with engineered intracellular costimulatory domains?

Answer 32

Longer T-cell surivival, effective tumour lysis & long-term regression