Interference No. 104,745
contemplated using a particular DNA expression vector in a yeast host strain to obtain hepatitis
B surface antigen (HBsAg), as recited in the count.28 The question was whether Hitzeman
should be credited with conception of using that process to obtain a hepatitis B surface antigen
having the specific form recited in the count, i.e., "in particle form having a sedimentation rate
which is virtually identical to that of authentic 22 nm hepatitis surface antigen particles." The
court, after holding that the particle size and sedimentation rate recitations are material
limitations, i.e., not to be treated as inherent in the other limitations, id. at 1354-55, 58 USPQ2d
at 1168-69, answered that question in the negative:
Nothing in the record suggests that Hitzeman had a reasonable expectation that
using yeast as a host cell, rather than bacteria, would yield successful assembly of
particles, which he specifically claimed. When a research plan requires extensive
research before the inventor can have a reasonable expectation that the limitations
of the count will actually be met, complete conception has not occurred.
[Citations omitted.]
Id. at 1357, 58 USPQ2d at 1169. The Hitzeman court distinguished this holding from
Burroughs's above-quoted holding that "[a]n inventor's belief that his invention will work or his
reasons for choosing a particular approach are irrelevant to conception," 40 F.3d at 1228,
32 USPQ2d at 1920, by noting that the question in Hitzeman was whether the inventor had a
28 The count contained two alternatives, of which the first read as follows:
A DNA expression vector capable of replication and phenotypic selection in [a]
yeast host strain comprising a promoter compatible with a yeast host strain and a
DNA sequence encoding hepatitis B surface antigen, said sequence being
positioned together with translational start and stop signals in said vector under
control of said promoter such that in a transformant yeast strain it is expressed to
produce hepatitis B surface antigen in particle form having a sedimentation rate
which is virtually identical to that of authentic 22 nm hepatitis surface antigen
particles[.]
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