Retroviral-mediated transfer and amplification of a functional human factor
VIII gene
DI Israel and RJ Kaufman
Genetics Institute, Cambridge, MA 02140.
Hemophilia A results from a deficiency in factor VII (FVIII), a cofactor in
the intrinsic pathway of blood coagulation. As an approach toward genetic
therapy of this disease, we constructed a retroviral vector encoding human
FVIII and a selectable and amplifiable genetic marker, human adenosine
deaminase (Ada). A retrovirus packaging line was transfected with this
vector and stable transformants were selected for Ada expression. Isolated
transformants produced both FVIII activity in the conditioned medium and
retrovirus capable of transferring the Ada selectable marker and FVIII
expression to the mouse 3T3 fibroblasts. Selection of virus-producer cell
lines for increasing levels of Ada expression yielded a 20-fold increase in
both FVIII expression and viral titer. Similarly, selection of infected 3T3
fibroblasts for Ada gene amplification yielded a 20-fold increase in FVIII
expression. The results demonstrate the feasibility of retrovirus- mediated
transfer of human FVIII, and also the utility of selection for gene
amplification to increase retrovirus titers in producer cell lines as well
as expression levels in infected cells.
Volume 75,
Issue 5,
pp. 1074-1080,
03/01/1990
Copyright © 1990 by The American Society of Hematology