Micro: Viral Vectors

Question 1

Briefly describe gene therapy, bro.

Answer 1

A novel approach to treating diseases based on modifying the expression of a person’s genes toward a therapeutic goal.

Question 2

Describe somatic gene therapy.

Answer 2

Involves the manipulation of gene expression in cells so as to be corrective for the pt. This correction not inherited by the next generation.

Question 3

Describe germline gene therapy.

Answer 3

Involves the genetic modification of germ cell that will pass the selected change on to the next generation.

Question 4

Are we using germline gene therapy in human models yet?

Answer 4

Nope. Just other animals.

Question 5

The vast majority of clinical trials involve the treatment of various types of _____ .

Answer 5

Cancer.

Question 6

Are there any FDA approved gene therapy products currently on the market in the US?

Answer 6

Nope.

Question 7

There are two types of intervention strategies for gene therapy applications. List and describe them, briefly.

Answer 7

1) Therapeutic strategies. A vector carries a gene that encodes a protein that is either defective or absent due to mutation(s) in the pt’s endogenous genes.
2) Cytolytic strategy. Vector is designed to destroy or eliminate a diseased cell or tissue.

Question 8

Most vectors for delivery of a gene therapy are based on:

Answer 8

attenuated or modified versions of viruses

Question 9

Describe the non-viral vectors for gene delivery.

Answer 9

Liposome transfection- complexes of DNA and lipids

“gene gun” technology- delivery of DNA on gold particles (primarily for DNA vaccines)

Question 10

Which vector would be ideal for delivery of a gene greater than 50kb?

Answer 10

Liposomes/Naked DNA

Question 11

Which vector elicits an immune response?

Answer 11

Adenovirus

Question 12

Which vector is episomal?

Answer 12

Adenovirus

Question 13

Which vectors infect both dividing and non-dividing cells?

Answer 13

Adenovirus, Adeno-associated virus, Herpesvirus

Question 14

Which vector has long term expression because it inserts the genome into the host cell’s DNA?

Answer 14

Retrovirus

Question 15

Which vector is in danger or being inactivated by human complement?

Answer 15

Retrovirus

Question 16

The vectors most commonly used in gene therapy trials are:

Answer 16

Adenovirus 24%, Retrovirus 19%, naked/plasmid DNA 17%

Question 17

Describe 3 problems that need to be resolved before gene therapy can become available as a true therapeutic tool for physicians.

Answer 17

1) how to avoid immune response in pt.
2) How to get genes into non-dividing cells like liver, muscle, and neurons and other specifically desired cell types other than those usually infected by the virus.
3) How to get the gene integrated so that it will be replicated and expressed indefinitely and as needed.

Question 18

Adeno-associated virus (AAV) gets its name because it is often found in cells that are simultaneously infected with _________. However, by itself, it seems to be harmless.

Answer 18

Adenovirus

Question 19

Does AAV stimulate inflammation in the host?

Answer 19

No sir.

Question 20

Does AAV elicit antibodies against itself?

Answer 20

No ma’am.

Question 21

Can AAV enter non-dividing cells?

Answer 21

Yes. Yes it can.

Question 22

AAV integrates successfully into one spot in the genome of its host. Where is this, exactly?

Answer 22

on chromosome 19 in humans