In re Kubin

Facts

Kubin and Goodwin claimed a patent on the isolation and sequencing of DNA molecules encoding a protein known as the Natural Killer Cell Activation Inducting Ligand (NAIL). NAIL is a specific receptor protein on the cell surface that plays a role in activating Natural Killer (NK) cells. They also claimed the discovery of a binding relationship between NAIL and a protein known as CD48. Therefore, they claimed a genus of isolated polynucleotides encoding a protein that binds CD48 and is at least 80 percent identical to amino acids 22-221 of SEQ ID NO: 2—the disclosed amino acid sequence for the CD48-binding region of NAIL. Their specification also disclose SEQ ID NO: 1, which recited the specific coding sequence of NAIL, and SEQ ID NO: 3, which recited the full NAIL gene. The specification also contemplated variants of NAIL that held the same binding properties. The Board of Patent Appeals and Interferences (the Board) rejected the claims as obvious under 35 U.S.C. § 103, based on the teachings of U.S. Patent No. 5,688,690 (Valiante) and 2 Joseph Sambrook et al., Molecular Cloning: A Laboratory Manual 43-84 (2d ed. 1989) (Sambrook). Valiante disclosed a receptor protein called “p38” that is found on the surface of human NK cells. Valiante taught that the p38 receptor is present on virtually all human NK cells and also disclosed and claimed a monoclonal antibody specific for p38 called “mAB C1.7.” The Board found that Valiante’s p38 protein was the same protein as NAIL. A monoclonal antibody is an antibody that is mass-produced in the laboratory from a single clone and that recognizes only one antigen. Monoclonal antibodies are useful as probes for specifically identifying and targeting a certain kind of cell. Valiante also taught that “[t]he DNA and protein sequences for the receptor p38 may be obtained by resort to conventional methodologies known to one of skill in the art.” Valiante further described a five-step cloning protocol for “isolating and identifying the p38 receptor,” but did not disclose either the amino acid sequence of p38 recognized by mAb C1.7 or the polynucleotide sequence that enclodes p38. Sambrook described methods for molecular cloning in general. The Board found that Kubin and Goodwin used conventional techniques described by Sambrook to isolate and sequence the gene that codes for NAIL, and also found that their claimed DNA sequence was “isolated from a cDNA library . . . using the commercial monoclonal antibody C1.7 . . . disclosed by Valiante.” Regarding SEQ ID NO: 2, the Board found that Valiante’s patent provided a reasonable expectation of success in obtaining a polynucleotide encoding p38, which was within the scope of the Kubin and Goodwin claim. Due to NAIL’s important role in the human immune response, the Board further found that “one of ordinary skill in the art would have recognized the value of isolating NAIL cDNA, and would have been motivated to apply conventional methodologies, such as those disclosed in Sambrook and utilized in Valiante, to do so.” Kubin and Goodwin appealed and the court of appeals granted review.