Gene Therapy Vectors

Front 1

retrovirus

Back 1

*carry info as RNA
*infect only dividing cells'
*max length = 8,000bp
*once in cell, travels to nucleus where RNA is converted to DNA by enzymes in the retrovirus
*integrates in random locations, but once integrated it will duplicate with dna of cell
*possibilities of bad integration, and immune response in pt

Front 2

adenovirus

Back 2

*carry info as double stranded DNA
*can infect both dividing and non-dividing cells
*you can engineer proteins on the virus' surface to make it specific for certain cell types
*max length = 7,500bp
*travels to cell's nucleus where it's genes are activated
*do not integrate with host cell's genome, because of this, the cell will discard the gene after a week or 2
*can cause immune response in pts

Front 3

adeno-associated virus

Back 3

*carry info as single-stranded dna
*can infect dividing and non-dividing cells
*need assistance of a 'helper' virus to replicate themselves inside cells
*can target specific cell types if engineered to do so
*max length = 5,000bp
*dna will integrate with host cell's genome, and 95% of the time it will integrate in a specific region on chrom. 19.
*will typically not cause an immune response.

Front 4

Herpes simplex virus

Back 4

*carry info as single stranded dna
*targets and infects cells of the nervous system
*max length = 20,000bp
*dna travels to cell's nucleus and it's genes are activated
*do not integrate with host cell's genome, but can stay in nucleus for a long time and replicates on its own, thus wont disrupt other genes in host cell
*can cause an immune responce

Front 5

liposome

Back 5

*circular pieces of dsDNA called plasmids
*when added to cells, the packets fuse to cell membranes and DNA is transferred to the cell.
*not specific for any one cell type
*no max length
*unless engineered to do so, dna will not integrate, effectiveness of integration is very low
*will not generate an immune responce. better suited for ex vivo gene therapy

Front 6

Naked DNA

Back 6

*circular piece of dsDNA called a plasmid. not packaged in a virus or liposome
*not specific to cell type
*no max length
*enters cells far less effectively than viruses
*plasmid is transported to the nucleus where it's activated
*can be engineered to enter genome, but effectiveness is very low.
*no immune responce and not toxic. better suited for ex vivo gene therapy.