In reading the abstract below, note that (2) is the paradigm now
being discussed by advocates of experimental human cloning; (1) is not being
presented as an option for humans in the current debate.
Cell 2002 Apr 5;109(1):17-27
Correction of a genetic defect by nuclear transplantation and
combined cell and gene therapy.
Rideout WM, Hochedlinger K, Kyba M, Daley GQ, Jaenisch R.
Whitehead Institute for Biomedical Research, 9 Cambridge Center,
02142, Cambridge, MA, USA
Immune-deficient Rag2(-/-) mice were used as nuclear donors for
transfer into enucleated oocytes, and the resulting blastocysts were
cultured to isolate an isogenic embryonic stem cell line. One of the mutated
alleles in the Rag2(-/-) ES cells was repaired by homologous recombination,
thereby restoring normal Rag2 gene structure. Mutant mice were treated with
the repaired ES cells in two ways. (1) Immune-competent mice were generated
from the repaired ES cells by tetraploid embryo complementation and were
used as bone marrow donors for transplantation. (2) Hematopoietic precursors
were derived by in vitro differentiation from the repaired ES cells and
engrafted into mutant mice. Mature myeloid and lymphoid cells as well as
immunoglobulins became detectable 3-4 weeks after transplantation. Our
results establish a paradigm for the treatment of a genetic disorder by
combining therapeutic cloning with gene therapy.