5.2 Ex-Vivo (In-Vitro) Gene Therapy

It involves the transfer of the genetic material to cells located outside the host. Following transfer of the genetic material to the cells, the cells are implanted back into the host. This type is also called the indirect method of gene transfer.

The advantages of such type of gene therapy are

-  Cells from the patient will not be rejected by the immune system

- Transferring the genes into cells in -vitro is more efficient.  In addition, using certain markers on the vectors, it may be possible to isolate the transfected cells.

The target cell to be used for ex-vivo gene therapy must satisfy some pre requisites among these they must be:

- Easily removed, and withstand the subsequent manipulation and reimplantation.

- Capable of dividing and passing their genetic material to their descendants

-  The cells should be able to express a range of gene products

Only few cell types meet these requirements such as bone marrow-derived cells, and skin cells. (Aoki, et al 1997, Overturf , et al 1998 and Kerr, 1998).