Appeal No. 1999-1397 Page 3
Application No. 08/303,924
relatively straightforward to differentiate and enumerate the basic WBC types, the
differentiation of different kinds of cells of the same subtype (i.e. subpopulations) is not
so simple.@ At times, Ait is desirable to periodically monitor the relative proportion of two
different subpopulations of lymphocytes,@ for example, T4 and T8 lymphocytes, but Aall
lymphocytes look very similar in terms of their volume, conductivity and light scatter.@
Brief, pages 2-3.
According to appellants, Kortright Aaddresses the exact problem noted above,
namely, . . . distinguish[ing between] two different subpopulations (e.g. T4 and T8
lymphocytes) of the same type of cells,@ but does so without measuring light scatter.
Brief, page 3. That is, Kortright Adiscloses a method in which a multitude of
>microspheres=, each labeled with antibodies which are specific to only one of the two
subpopulations, are mixed with a whole blood sample. After mixing, the labeled
microspheres couple to those cells . . . of a selected subpopulation to form
cell/microsphere complexes . . . [S]ince the cell/microsphere complexes have volume
and conductivity characteristics that differ from the non-complexed cells alone, a
desired subpopulation of cell can be differentiated by . . . measur[ing] only cell volume
(DC), cell conductivity (RF), and cell opacity (RF/DC).@ Id.
Rodriguez describes an instrument that differentiates between lymphocytes,
monocytes, eosinophils, neutrophils and basophils using volume, conductivity and light
scatter measurements.
According to the examiner, A[i]t would have been obvious . . . to measure both
light scatter and the DC and RF electronic signals taught by Rodriguez . . . in the
method of Kortright . . . because Rodriguez [teaches] the combination of light scatters
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