Appeal No. 2001-2379 Page 8
Application No. 08/931,666
barrier, and then diffuse across the cytoplasm before being exocytosed on the
other side. See the Examiner’s Answer, page 6. The examiner argues that this
would have led those of skill in the art to expect that “this cytoplasmic stage of
the transport process would then make the antibody available for binding to
intracellular antigens.” Id.
The evidence of record does not support the examiner’s position.
Appellant have provided evidence that those of skill in the art would not have
expected cationized antibodies to be available for antigen binding during the
cytoplasmic stage of traversing the blood-brain barrier. The instant specification
cites Pardridge1 as disclosing that transcytosis across the blood-brain barrier
involves diffusion “presumably in nonclathrin-containing smooth vesicles.” Thus,
the evidence suggests that those of skill in the art would have understood
Triguero’s reference to cationized antibodies diffusing through the cytoplasm to
mean diffusion of the antibodies in vesicles. The examiner has pointed to no
evidence supporting an alternative reading of the reference, which would show
that those skilled in the art would have expected the antibodies to diffuse freely
through the cytoplasm and be available to bind to intracellular targets.
In addition, the evidence shows that many cells, including lymphoid cells,
commonly degrade endocytosed material in lysosomes. See Renau-Piqueras,
page 745 (“As is well known, lysosomal degradation of endocytosed material is
common in many cell types, including resting and stimulated lymphoid cells.”).
1 Pardridge, “Receptor-mediated peptide transport through the blood-brain barrier,” Endocrine
Reviews, Vol. 7, No. 3, pp. 314-330 (1986), of record.
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