Question

In the case of Jesse Gelsinger, a young man who died during gene therapy, the therapy involved delivery via a viral vector. Was this germ-line or somatic therapy?

Answer 1

In germ line gene therapy, germ cells (sperm or eggs) are modified by the introduction of functional genes, which are integrated into their genomes. This will allow the therapy to be hereditary and carry on to later generations.

In somatic gene therapy, therapeutic genes are introduced into a patient's somatic cells or body. Any modifications and effects will be limited to the individual patient and will not be inherited by the patient's offspring or future generations.

There are two general approaches to transfer genes into a cell

• Viral
• Non viral

Non-viral vectors are safe, can be constructed and modified in simple ways, and show high gene encapsulation ability. Non-viral vectors consist of naked DNA by injection, liposomes, nanoparticles and other ways.

Viral vectors are very efficient at introducing genes, but can also pose some safety risks.The viral vectors include RNA virus such as retrovirus and DNA virus such as adenovirus, Herpes simplex virus and Adeno-associated virus (AAV), and poxvirus.

Thus in the case of Jesse Gelsinger, therapeutic genes are introduced into the somatic cells via a viral vector. Who died in a clinical trial at the University of Pennsylvania. For the treatment they use a modified Ad5 vector to deliver the gene for ornithine decarboxylase, which is a deficient hepatic enzyme. Gelsinger died due to a massive immune response to the Ad5 vector.