to the detection of the antigen human alphafeto protein (AFP). Example 3 relates to the detection
of another antigen, human fibronectin (HFN). Engvall Application 06/539,754, specification, pp. 9-
15. The examples include a detailed explanation of the preparation of the respective monoclonal
antibodies for the antigens, bonding of the monoclonals to a substrate, labeling of the antibodies and
determination of the antigens. The examples do not mention affinity or the affinity constant of the
antibodies and antigens used.
The original claims of the application which are, of course, part of Engvall's written
description, are directed to a method for the determination of antigen. The claims are presented in
Jepson format. The improvement is said to be in using as the monoclonal antibodies which react with
sterically spaced determinants of the antigen. Again no reference is made to affinity. Engvall
Application 06/539,754, specification, pp. 16-17.
Thus, Engvall's specification unquestionably discloses the use of monoclonal antibodies in
sandwich assays, and, while making some general references to affinity, is devoid of any indication,
appreciation or guidance that any particular value for the affinity constant was of importance.
Engvall’s specification contains no express statement or implicit description that would lead the
person of ordinary skill in the art to use monoclonal antibodies and antigens having any particular
value of the affinity constant.
4. Inherency of the lower limit of “at least about 10 liters/mole” based8
on the data in Engvall’s example 1
Engvall does not urge that there is express language or equivalent language in the
specification which provides a basis for the specific affinity constant limitation. Rather, Engvall
asserts that the limitation inherently finds basis in her Example 1. Engvall Brief, pp. 94-102, Engvall
Reply Brief, pp. 2-10. At the outset, we note that if any of Engvall’s examples had expressly stated47
that both antibodies used had an affinity constant of 10 liters/mole, Engvall may have had written8
descriptive support for adding a claim utilizing 10 liters/mole as a lower limit. Absent, an express8
or implicit statement, the evidence must show that the person having ordinary skill in the art repeating
47
In this regard, Engvall’s briefs are somewhat confusing due to the apparent failure to distinguish
between claims and counts. The subject matter of the count is not relevant to the description requirement issue.
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