Appeal No. 2002-1299 Page 5
Application No. 08/962,740
the generality of STAT1 involvement in cytokine signaling and to probe the roles
of STAT1-linked pathways under physiologic settings and during development,
[Durbin] … disrupted the gene for STAT1 in embryonic stem (ES) cells and in
mice.”
Therefore, to the extent that appellants would argue that Durbin should be
limited to the study of Stat1 in vivo we do not agree. Not only does Durbin
discuss earlier studies performed with cell lines (page 443), Durbin study
Stat1-/- ES cells and produce Stat1-/- animals. We also note Durbin’s discussion
of the difficulty in maintaining homozygous Stat1-/- animals. (Durbin, page 445,
column 2, “no homozygous animal born in this initial colony has survived greater
than 8 weeks … [however] Stat1-/- animals obtained in … [a pathongen-free]
colony displayed no symptoms of spontaneous disease.”). In contrast, the
examiner points out (Answer, page 5), immortalized cell lines are “an easier
vehicle to study the interactions of cytokines and Stat1 proteins. Immortalized
cell lines can be readily multiplied and grown to run a plethora of assays much
more quickly than the mouse itself.” We note that the examiner’s comments are
supported by Leder. Leder, column 3, lines 50-60.
In disclosing a method for providing a cell culture from a transgenic non-
human mammal, Leder state (id.):
The animals of the invention can also be used as a source of cells
for cell culture. Cells from the animals may advantageously exhibit
desirable properties of both normal and transformed cultured cells;
i.e., they will be normal or nearly normal morphologically and
physiologically, but can, like cells such as NIH 3T3 cells, be
cultured for long, and perhaps indefinite, periods of time. Further,
where the promoter sequence controlling transcription of the
oncogene sequence is inducible, cell growth rate and other culture
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