Appeal No. 1996-2013
Application No. 07/935,695
The invention thus can provide intact biosynthetic antibody binding sites
analogous to V -V dimers, either non-covalently associated, disulfide
H L
bonded, or preferably linked by a polypeptide sequence to form a composite
V -V or V -V polypeptide . . . The invention also provides proteinsH L L H
analogous to an independent V or V domain, or dimers thereof.H L
Further, on page 26 (references to figures omitted), Huston teaches that:
The linker 12 should be long enough . . . to permit the chains to assume their
proper conformation . . . [T]he linker may comprise an amino acid sequence
patterned after a hinge region of an immunoglobulin . . . The linker may also
include one or two built in cleavage sites . . . This strategy permits the V and
H
V -like domains to be separated after expression, or the linker to be excised
L
after folding while retaining the binding site structure in non-covalent
association.
On page 28, Huston discloses a linked pair of BABS, i.e., a dimer of single chain
polypeptides. We cannot agree with the examiner’s conclusion that these are “dimeric
single chain antibody fragments which are non-covalently dimerized” (Examiner’s Answer,
page 4, emphasis added). The BABS are linked through a spacer, which “may be an
amino acid sequence analogous to the linker sequence [ ] or it may take other forms.”
According to Huston, “the spacer’s primary function is to separate the active protein
regions to promote their independent bioactivity and permit each region to assume its
bioactive conformation independent of interference from its neighboring structure” (page
28). This does not describe the non-covalent linkage between individual single chain
polypeptides required by the claims on appeal.
This deficiency in the primary reference is not remedied by any of the secondary
references. In our judgment, the combined disclosures of the cited references are not
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