Appeal No. 94-1696
Application 07/811,129
In the case before us, the specification provides only two
working examples of fusion proteins which are capable of binding
to CD11a/CD18; i.e., fusion proteins comprising ICAM-1 or ICAM-2.
The specification fails to provide any guidance as to (i) the
construction of fusion proteins comprising other, structurally
different, polypeptides, such as those indicated by Makgoba,
supra, which have the claimed binding specificity, or (ii) how to
identify and isolate other such polypeptides. Moreover, the
structural features of molecules having the claimed binding
characteristics are unpredictable. That is, it is not possible
to predict the structure of an LFA-1 ligand from the disclosed
ICAM-
1 and ICAM-2 sequences. Accordingly, in view of the breadth of5
the claim language, the limited number of working examples, the
unpredictable nature as to the types of ligands capable of
binding to the LFA-1 receptor, we hold that one skilled in the
5We note that the specification discloses that “the two
most N-terminal domains of ICAM-1 and ICAM-2 which contribute to
their interactions with LFA-1" only have 34 % identity on the
amino acid level. Specification, p. 12, lines 26-27. Moreover,
ICAM-1 has three additional “immunoglobulin-like” domains which
appear to play a role in the avidity for LFA-1. Specification,
sentence bridging pp. 12-13.
12
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