Biotechnology 3 - monoclonal antibodies

Question 1

What does B lymphocytes do?

Answer 1

Produce antibodies that can inactivate the foreign protein and mark the protein/cell for destruction

Question 2

Model of antibody

Answer 2

Constant region,
variable region: where it binds to the antigen- everyone’s will be different here,
This site determines the specificity of the antibody

Question 3

Polyclonal antibodies are?

Answer 3

Lot of different types (mixed) of antibodies working on different sites of one antigen- they never work as drugs because it is all different, different in people too

Question 4

Monoclonal antibodies are?

Answer 4

recognise one specific site of antigens (epitope)
Homogeneous proteins (produced by a single clone of B-cells)

Question 5

What is epitope?

Answer 5

The bit where antibody binds
every single antibody in a monoclonal product bind to this bit and nowhere else.
You can make a drug!
as everyone’s antibodies only recognise the same single epitope

Question 6

How to make monoclonal antibodies?

Answer 6

1. hybridoma technology

Question 7

Problem with making monoclonal antibodies

Answer 7

easy to isolate and produce from cultured IMMORTAL cells but these do NOT MAKE ANTIBODIES

B-cells produce antibodies BUT they are NOT immortal

Question 8

How to overcome the problem of monoclonal antibody production?

Answer 8

By making a hybrid! (antibody producing cell + immortal cell)

Question 9

Hybridoma technology

Answer 9

1. Inject a mouse with antigen
2. Mouse produces antibodies (polyclonal, b-cells)
3. Fuse the proteins together in different ways (antibody + antibody, antibody + b-cell–>hybrid, b-cell + b-cell)
4. Make a hybridoma and culture it in the special media
5. Immortal cells do not survive because he has no key gene, B-cells cannot survive because they are not immortal
6. Only hybridomas survive
7. Select the best clone, test it and grow it (never pool them together!)
8. Grow the clone up to make it infinite amount of cells
9. Inject it back to animal –> grow tumours (VERY CRUEL) or grow them in culture (in a big tank)

Question 10

Uses of monoclonal antibodies

Answer 10

Pregnancy/ovulation diagnosis

Imagining and pathology (theranostics), therapy

Question 11

What is theranostics

Answer 11

Therapeutic (gene therapy, chemo, radioation, photodynamic) + diagnositc (MRI,PET,MRI)

Question 12

How to reduce the immunogenicity of monoclonal antibodies

Answer 12

Chimeric mAb,
Humanised mAb,
Human mAb

Question 13

What is chimeric mAb?

Answer 13

constant region is human
variable region is mouse
we can’t tell which one is chimeric or humanised

Question 14

What is humanised mAb?

Answer 14

Everything is human EXCEPT for the bit where it binds to the antigen

Question 15

What is human Ab?

Answer 15

Entirely human antibody

Knockout every single immune system in the mouse and replace it with human immune system

Question 16

Example of humanised monoclonal antibody

Answer 16

Trastuzumab (Herceptin)

Question 17

What does trastuzumab do?

Answer 17

targets Her2 protein (turns on proliferation of cells), overexpressed in many breast cancer pt

Question 18

New generation

Answer 18

monoclonal antibodies are not blockbusters

Linking the antibody (trastuzumab) with cytotoxic drug (which treats cancer)
–> we can deliver the very toxic drug to a specific area to where cancer is, to reduce any SE lie hair loss

Question 19

Key components in the new generation

Answer 19

MCC (linker) = highly stable in circulation,

allows release of cytotoxic moiety within the cell