Aptamers and therapeutic antibodies

Question 1

process of making an aptamaer

Answer 1

• the nature of aptamer is an RNA
• RNA can change into many different forms
• target protein (thought to be causing the disease) is added to a mixture of aptamers
• wash away any aptamers which don’t bind
• isolate these RNA and add target protein again, this time washing away lower affinity ran
• then after aptamers with strongest affinity to protein is found, it is strengthen so it will not break down in the body

Question 2

Therapeutic antibodies; Fab fragments process

Answer 2

1) fuse the cDNA or a Fab to a phage coat protein
2) genetically engineer a library of bacteriophages with many different cDNA sequences
3) expose phages to an immobilised target molecule
4) use high stringency washes to leave the strongest binders attached to the ligand
5) elute stronger binders
6) use strong bidders to infect bacteria
7) natural mutations will occur as the bacteria grow and new phages will be produced
8) variants of themes are produced and repeat process- expose phages to the immobilised target molecule
9) use high stringency washes to leave the strongest binder
10) elute the binders
11) increase wash stringency
12) add back to bacteria so natural mutations occur, meaning new phages of the same theme are produced
13) third generation phages produced
- repeat cycle until super high affinity binders

Question 3

benefits of these processes

Answer 3

• no class specific toxicity
• can be rationally engineered and optimised
• non immunogenic
• moderate cost
• only requires a few cycles

Question 4

what are aptamers

Answer 4

short strings of nucleotides (oligonucleotides) which when placed in solution with proteins form a 3D structure

Question 5

example of what a 3D structure could be

Answer 5

DNA cage

Question 6

Aptamers as DNA cages

Answer 6

used to transport drugs/ toxin to target tissues

• travel in the blood to target tissue
• bind to specific surface receptors
• causes cage to open and delivers drug to the target tissue

Question 7

aptamers are examples of

Answer 7

targeted drug delivery and personalised medicine

Question 8

therapeutic antibodies can be used to

Answer 8

target antibodies to make sure they take a plasmid up