Cells including targeted chromosome 21 were killed in this selection medium because of HSV-tk genes present in the target fragment.
Therefore, extra copies of chromosome 21 integrating the DNA cassette may tend to be lost from the HeLa cells spontaneously under condition in which cells including HSV-tk gene are excluded.
Aguilar-Cordova et al., "Phase I study of adenoviral delivery of the
HSV-tk gene and ganciclovir administration in patients with recurrent malignant brain tumors," Molecular Therapy, vol.
Construction of retroviral vector and determination of retroviral titre: After confirming orientation ofthe
HSV-tk gene cloned in pLTKSN it was co-transfected into 293 cells with an ecotropic helper virus pEcoLandau to produce ecotropic viral particles.
The clinical trials have confirmed that the
HSV-TK gene therapy was superior to conventional treatments in the primary endpoints, especially in survival rates.
The Shiga Prefecture-based Takara Bio, a subsidiary of Takara Holdings Inc., expects the techniques to draw a total of about 45,000 latent patients, with 20,000 for treatment with
HSV-TK gene, another 20,000 for HSV-TK-MAGE3 genes and 5,000 for AIDS.