Ab

Question 1

Polyclonal Ab

Answer 1

Mix of Ab against different epitopes of an Ag, originating from different Bc’s. E.g. isolated from blood plasma after injection of Ag.

Question 2

Monoclonal Ab

Answer 2

mAb are produced by one BC line, that produces one antibody, that binds specifically one epitope of an Ag with a specific binding affinity.
Produced by Hybridoma cells = fusion of BC with an immortalized cell

Question 3

How would you isolate Ab producing BC from human plasma?

Answer 3

Labeled Ag, for which the Ab is wanted is added to Isolated serum containing BC. BB producing wanted Ab are binding to labeled Ag. Then flow cytometry, to sort out the wanted Ag-BC complex

Question 4

What is Function based drug discovery ?

Answer 4

In function based discovery, the functionality of the drug is optimized and then the optimal target is identified afterwards. E.g. Different Ab are used and screened for the wanted function (e.g. induction of ADCC) and then the best Target is Identified.

Question 5

How would the workflow for discopvering an Ab medication look like?

Answer 5

Ab;fragment development
Primary high throughput screening for useful Ab against target
Sequencing of promising candidate
Affinity measurement
Specificity screening (–> on target and off target tox)
Orthogonal screening - different tests to confirm findings
Reformation of full Ab (with wnated functions e.g. FcRn binding, Payload…)
Functional assay (e.g. ADCC, checkpoint inhibition)

Question 6

How can you measure the Epitope specifity?

Answer 6

• Immunoassays (ELISA)
• SPR
• Xray crystallography
• HDX-MS

Question 7

What are Bispheric Ab?

Answer 7

Binds two different targets with the Fab regions –> e.g. the tumor cell and a CD8+ (cytotoxic) TC to induce the killing of the tumor cell

Question 8

Phage display

Answer 8

Geneticlaly modefied phages are used to express a variety of Phage-Ab against a large collection selected Ag. The Library size extends 100 billion.
The phages displaying the Phage-Ab are used to ID the best fitting Ab for a given Ag.

Question 9

At the example of HER2+ tumors explain three mechanisms that Ab therapy could be used to treat the disease

Answer 9

• Inhibition of dimeristion of the HER2 receptor –> stops the signal cascade (RAS RAF ,….)
• Receptor internalisation;degradation
• ADCC (Antibody dependent cellular cytotoxicity) - Ab carries Fc for NK or DC FcR

Question 10

What are Ab drug conjugates (ADC)?

Answer 10

Antibody that is linked to a small molecule drug e.g. chemotherapeutic. The Ab binds a tumorspecific Ag, is internalized and the linker releases the drug pH dependent in the endosome.
- Bystander effect = the chemotherapeutica also attacks the cells neibouring the tumor cells (increased effectiveness, since most of them are also tumor cells)
- Individual dosing with the amount of payload conjugated to the Ab