Sustained expression of high levels of human factor IX from human cells implanted within an immunoisolation device into athymic rodents.
Immunoisolation of allogeneic cells within a membrane-bound device is a unique approach for gene therapy. We employed an immunoisolation device that protects allograft, but not xenograft, cells from destruction, to implant a human fibroblast line (MSU 1.2) in athymic rodents. Cells, transduced with the MFG-human factor IX retroviral vector, and expressing 0.9 microg/10(6) cells/day in vitro, were implanted in rats (four 40-microl devices, each containing 2 x 10(7) cells, two subcutaneously, two in epididymal fat) and in mice (two 20-microl devices, each containing 2 x 10(6) cells, subcutaneously). Plasma factor IX levels increased for 50 days, reaching maxima of 203 ng/ml (rat) and 597 ng/ml (mouse), and both continued at greater than 100 ng/ml for more than 140 days. A clone derived from the transduced cells, making 5 microg of factor IX/10(6) cells/day, was implanted within a device (one 20-microl device containing 2.5 x 10(6) cells), or without a device (1 x 10(7) cells implanted freely), either subcutaneously or in epididymal fat. The freely implanted cells expressed transiently, reaching more than 100 ng/ml in each site by day 4, but dropped to zero by day 20 (subcutaneous) or day 90 (epididymal fat). In devices, levels gradually increased to 100 ng/ml (subcutaneous) or 300 ng/ml (epididymal fat), remaining high for more than 100 days. These results show long-term, high-level expression of a human protein: (1) when cells are implanted within a cell transplantation device, but not when the cells are freely implanted, and (2) from a transgene driven by a viral promoter. An alloprotective device will enable the use of cloned cell lines that can be subjected to stringent quality control assessment that is impossible to achieve with autologous approaches.
Brauker
J
J
Gene Therapy Unit, Baxter Healthcare Corp., Round Lake, IL 60073, USA.
Frost
G H
GH
Dwarki
V
V
Nijjar
T
T
Chin
R
R
Carr-Brendel
V
V
Jasunas
C
C
Hodgett
D
D
Stone
W
W
Cohen
L K
LK
Johnson
R C
RC
D000818:Animals; D017690:Cell Transplantation / Q000295:instrumentation* / Q000379:methods*; D005164:Factor IX / Q000096:biosynthesis / Q000235:genetics*; D005347:Fibroblasts / Q000378:metabolism / Q000637:transplantation; D005818:Genetic Engineering; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D051381:Rats; D011923:Rats, Nude; D014162:Transfection; D019076:Transgenes; D014181:Transplantation Immunology
D005164:Factor IX