Appeal No. 1999-1245
Application No. 08/245,282
co-stimulation and T-cell activation following ligation by B7, but provides no reason,
suggestion or motivation to inhibit such a metabolic pathway. Ward 1993 concludes
that, “The possible activation of PKC. in T cells ... by D-3 phosphoinositides following
CD28 receptor ligation and its relevance to T cell activation and co-stimulation remains
to be established.” Ward 1993, pages 2576-2577. Vandenberghe would appear to
suggest that CD28-induced tyrosine phosphorylation can be prevented by CD45 and
herbimycin A, and that herbimycin A prevents CD28-stimulated IL-2 production.
Vandenberghe is particularly deficient in the discussion of any metabolic or enzymatic
pathway involved in such inhibition, but would only speculate that tyrosine kinase be
somehow involved in signal transduction. Vandenberghe, page 951. What is missing
from the examiner’s analysis is appropriate evidence establishing that the inhibitor of
tyrosine kinase described by Vandenberghe would have the same specificity, and also
act on PI 3-kinase. Again, a determination that claimed subject matter is prima facie
obvious must be supported by evidence, as shown by some objective teaching in the
prior art or by knowledge generally available to one of ordinary skill in the art that would
have led that individual to combine the relevant teachings of the references to arrive at
the claimed invention. See In re Fine, 837 F.2d 1071, 1074, 5 USPQ2d 1596, 1598
(Fed. Cir. 1988). In our view, the cited references do not reasonably appear to provide
evidence of inhibiting a response by a T cell expressing a CD28 cell surface receptor
which binds a costimulatory molecule, by contacting the T cell with an agent which acts
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