Appeal No. 1997-2391
Application 08/239,265
The examiner believes that it would have been obvious to combine anti-CD45 and
anti-CD71 monoclonal antibodies in Loken’s method because “[Loken] teach[es] the
combination of nucleic acid dyes and anti-CD45 as providing a distinction between only
mature erythrocytes and reticulocytes, and not identifying earlier precursors to the
erythrocytes” while “[Kansas] teach[es] antibodies to CD71 in combination with anti-CD45
as providing a means of distinguishing erythroid precursors and proliferating cells” (Office
Action mailed December 13, 1994, Paper No. 14).
We do not agree. As appellants point out, Kansas focuses on expression of three
specific leukocyte adhesion molecules (CD11/CD18, LAM-1 and CD44) during normal
myeloid and erythroid differentiation (Brief, page 6). The appearance and subsequent
disappearance of CD71 and CD45 during erythropoiesis are mentioned in passing, and
then only in the larger context of the gradual, stepwise decline in CD44 expression during
erythropoiesis. While one would recognize from Kansas that CD71 and CD45 are
differentially expressed during erythropoiesis, the discussion of their occurrence at various
stages of cell maturity is fragmentary, especially in comparison with the discussion of
CD44 expression. It is only with the use of impermissible hindsight that Kansas can be
considered to suggest CD71 and CD45 expression patterns as “a means of distinguishing
erythroid precursors and proliferating cells.”
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