Appeal No. 2004-2134 Page 9
Application No. 09/425,075
taught by Horwitz, see Robinson, col. 16, lines 21-34 and col. 44, Example 5, but
also teaches that an alternative approach for simultaneously expressing both
light and heavy chains in yeast is to attach the light and heavy chains to a yeast
promoter and a terminator sequence and place both expression cassettes on the
same plasmid, see id. at col. 16, lines 15-20. The combination thus teaches that
one can use a single vector, dual cassette expression system, to express
functional immunoglobulin in the yeast S. cerevisiae.
The rejection relies upon Cregg and the Invitrogen catalog for their
teaching of the use of the yeast, Pichia pastoris, for the production of
heterologous proteins. As noted by the rejection, see Examiner’s Answer, page
5, Cregg teaches that problems exist with scaling up the production of
heterologous proteins in yeast, and teaches that in light of those problems, a
second-generation yeast expression system, Pichia pastoris, has been
developed as a host system for the efficient, large-scale production of
heterologous proteins. We therefore find it would have been obvious to the
ordinary artisan at the time of invention to substitute the Pichia expression
system in the S. cerevisiae dual cassette, single vector expression system as
taught by Robinson and Horwitz because of the advantages of the Pichia
expression system as taught by Cregg and the Invitrogen catalog.
Appellants argue further that the art provides no reasonable expectation of
success, and that the art in fact teaches away from the claimed invention. See
Appeal Brief, page 12. First, appellants rely on Pinnell for teaching that “‘The
size of the protein to be expressed may also be limiting because to our
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: November 3, 2007