Appeal No. 1998-0968
Application No. 08/031,075
The examiner does not, however, rely on extrinsic evidence in concluding that
Nahm’s antibody inherently binds mammalian cells. In this regard, appellants argue that
the terminal N-acetylglucosamine on the group A Streptococcal carbohydrate is attached
through carbon atom 1 to carbon atom 3 of rhamnose by a $1 linkage, while a terminal N-
acetylglucosamine on a mammalian cell is attached through carbon atom 1 to carbon atom
2 of mannose by a $1 linkage. The implication is that an antibody specific for a
determinant involving the attachment of N-acetylglucosamine to rhamnose will not
necessarily bind N-acetylglucosamine attached to mannose. Brief, pages 23 and 24. In
our view, this is not a completely satisfactory argument as it does not come to grips with
the fact that HGAC-1 binds N-acetylglucosamine conjugated to BSA, and thus recognizes
the N-acetylglucosamine hapten itself, rather than its point of attachment to the Group A
carbohydrate.
Additionally, appellants rely on the declaration of Dr. Rook (paper no. 22, April 14,
1993; resubmitted as Exhibit D with the Brief), wherein Dr. Rook contends that “[m]ost
monoclonal antibodies . . . raised against the bacterial cell walls of Group A Streptococcus
do not have the properties of the monoclonal antibodies of the present invention (the ability
to bind to mammalian cells or membranes . . . containing terminal N-acetylglucosamine
residues).” This is a statement of fact, which we accept at face value. Nevertheless, it is
conspicuous for what it does not say. N-acetylglucosamine is a major antigenic
determinant on group A strep, but it is not the only one. Clearly, some antibodies raised
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