iii. Engvall’s estimate of the affinity constant
Engvall further urges that because of the results of the assay shown in her example 1
-9
measured nanomoles per liter (10 moles/liter) or less, the liquid phase antibody necessarily has an
9
affinity greater than 10 liters per mole or higher. Engvall Brief p. 99-100; Reply Brief, p. 8. In this
regard, Engvall testified (ER 3190):
You know that if you can measure nanomoles per liter of an antigen,
the affinity of your antibodies are going to be nanomoles per liter.
Even if Engvall is correct in this assertion, “10 or higher” does not reasonably and necessarily lead9
the person having ordinary skill in the art to use a lower limit of about 10 liters/mole. 8
b. The affinity constant of the carrier-bound antibody
With respect to the affinity constant for the antibody bound to a solid carrier, the evidence
indicates that it is not possible to directly calculate the affinity constant from the data in Engvall’s
example 1. For example, the Scatchard Plot analysis only provides information about the labeled,
liquid-phase antibody, not the carrier bound antibody. Thus, the Walker article indicates that the
results of the Scatchard Plot analysis refer “to the labeled antibody in solution and are not related to
the concentration or avidity of the antibody initially present on the solid phase.” E57, p. 589. A
publication by Rodbard et al. (GCX141 ) indicates that the reaction system involved in an57
immunometric assay is extremely complex involving numerous rate constants and other factors.
GCX141, p. 81, col. 1. Consistent with the Rodbard publication, Langone testified that “[t]he
binding affinity for the immobilized antibody cannot be determined directly from the data given in
example 1, because that antibody is immobilized on the plastic.” ER 3495. Bergland similarly
testified that it was not possible to determine the affinity constant for the antibody bound to a solid
carrier. The following exchange took place during her cross-examination (ER 1980):
Q. Turning now to your estimation of the affinity constant for the
solid phase antibody in example 1 of the Engvall patent
application, there is no mathematical way to derive the affinity
constant, is there?
A. No.
57
“GCX” refers to Gallati Cross Exhibits. Gallati was a party to this interference. Gallati conceded
priority and judgment was awarded against Gallati in Paper 281.
35
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