Gene Therapy

Question 1

What was the first ex vivo therapy used to treat?

Answer 1

Treating Adenosine Deaminase Deficiency Syndrome (bubble boy syndrome)

Question 2

What was the first in vivo gene therapy used to treat?

Answer 2

Cystic fibrosis, using adenovirus

Question 3

What are the two types of classical gene therapy?

Answer 3

Somatic and Germline, with only somatic done in humans currently

Question 4

Explain the overall process of ex vivo therapy

Answer 4

A tissue is removed, and treated with a retrovirus. The cells that incorporated the virus are then selected and injected back into the patient.

Question 5

What are types of problems treated by gene therapy or in clinical trials?

Answer 5

Genetic deficiencies (i.e. OTC deficiency), Viral Infxns, Cancer, Autoimmunity, Diseases with genes and environmental intxn.

Question 6

What are the most commonly research health issues being researched for gene therapy?

Answer 6

Cancer, monogenic diseases and cardiovascular diseases

Question 7

What is the first gene therapy to be approved for treatment of disease? Where is it?

Answer 7

Glybera is used to treat lipoprotein lipase deficiency in Europe, and treats congenital blindness

Question 8

What are the two types of intervention strategies for gene therapy applications?

Answer 8

Therapeutic strategies and cytolytic strategies

Question 9

What is the most significant challenge in gene therapy?

Answer 9

Delivery of the gene therapy to a given target in a specific, safe and efficient manner

Question 10

What are the two general methods of gene therapy

Answer 10

Using vectors from modified viruses or non-viral vectors

Question 11

What is a challenge of using viral vectors

Answer 11

One must remove the disease causing agents of the virus and insert recombinant genes that will be therapeutic

Question 12

What are examples of non-viral vectors?

Answer 12

Liposome transfection - complexes of DNA and lipis

Gene Gun technology - delivery of DNA on gold particles (primarily for vaccines

Question 13

What is a concern when needing to do multiple doses?

Answer 13

If it’s a vector that doesn’t integrate into the host DNA, it cannot cause an immune response or the person will be immune to future doses.

Question 14

What are the five categories of Vectors?

Answer 14

Adenovirus, adeno-associated virus, herpesvirus, liposomes/naked dna, retrovirus

Question 15

What are the most commonly used vectors in gene therapy?

Answer 15

Adenoviruses and retroviruses

Question 16

What types of cells can adenoviruses infect?

Retroviruses?

Answer 16

Adenoviruses infect replicating and non-rep cells

Retroviruses can only target replicating cells

Question 17

What is the one retrovirus can enter into replicating and non-replicating cells?

Answer 17

HIV

Question 18

Must add card based on the creation of retroviruses

Answer 18

yea…

Question 19

What are three big problems to be solved for gene therapy to take off?

Answer 19

How to avoid immune responses, how to get genes into non-dividing cells like liver, muscle, and neurons, and how to get gene integrated so it will be expressed indefinitely

Question 20

What are lentiviruses?

Answer 20

Viruses that have latency or extended periods that they remain in the body like HIV

Question 21

What are four important differences between AAVs and other vectors?

Answer 21

AAVs:

• don’t stimulate inflammation in the host
• don’t elicit antibodies against itself
• can enter non-dividing cell
• integrates successfully into one spot in the genome of its host (still low freq)

Question 22

What is an example of gene therapy success?

Answer 22

SCID, which resulted in 90% of treated infants becoming better

Question 23

How is the treatment of leber congenital amaurosis?

Answer 23

Mutations of RPE65. A recombinant adeno-assoc. virus vector, altered to fix gene, restored vision in animal models.

Question 24

What is insertional oncogenesis?

Answer 24

Possible risk with type of vector, because they repeatedly insert into cell’s chromosomes, the process that is most likely to lead to a malignant change.

Question 25

Adenovirus vector properties

Answer 25

episomal, high transductino efficiency, infects replicating and non-replicating cells, elicits an immune response, insert capacity 8-36 kb

Question 26

adeno-associated vector properties

Answer 26

gold standard, integrates genome into specific region on human chromosome 19 long lasting, low immunogenicity, no associated disease, infects both dividing and non-dividing tissues, limited insertion capacity

Question 27

Herpes vector properties

Answer 27

large insertional capacity, broad host range, infects dividing and non-dividing cells

Question 28

liposomes/naked dna vector properties

Answer 28

no limit to size of genes, low immunogenicity, poor levels of gene transfer

Question 29

retrovirus vector properties

Answer 29

non-pathogenic, in dividing cells, inserts into genome, long term expression, insert capacity of 8 kb, inactivated by human complement