Appeal 2007-1161
Application 09/954,166
components” which have a “very different secondary structure” from
immunoglobulin chains, and therefore the skilled worker would not have
been motivated to replace its leucine zipper with immunoglobulin chains to
enhance T-cell heterodimer interactions (Br. 14).
In regard to Harris, Appellants state:
Harris explicitly teaches one of ordinary skill not to
include a complete immunoglobulin molecule in its binding
proteins. In fact, use of a complete immunoglobulin molecule
would render the Harris binding proteins unsatisfactory for one
of their intended purposes (to avoid undesirable effector
functions). There is, therefore, no suggestion in Harris to
include both heavy and light immunoglobulin chains, which are
present in molecular complexes of the invention.
(Br. 15).
Finally, Appellants contend that it was well known that TCRs
associate to form functional binding sites in the absence of their
transmembrane domain, so no additional manipulations would have been
necessary as suggested by the Examiner (Br. 15). Accordingly, they
conclude that even if there were reason to modify Dal Porto, “the
modification would have been to substitute one of the TCR or class II MHC
extracellular domains for the MHC class I α chain in the fusion protein, to
express the other extracellular domain by itself, and to permit the two
extracellular domains to associate as the prior art taught they would” (Br.
15).
In our opinion, the Examiner has the better arguments. Matsui’s
teaching of the low-affinity of soluble heterodimeric TCR (Matsui, p. 12862
(Abstract); Findings of Fact 5) coupled with Dal Porto’s teaching that both
the affinity and effectiveness of soluble MHC can be improved by grafting
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