definiens: . Field shall mean the discovery, isolation, characteri zation, research, development, and/or commercialization of an Antibody useful for the diagnosis, treatment and/or of one or more of the disease conditions -11 - Confidential Treatment Requested by letter dated February 1 .. 0, 2002 For the purpose of this Agreement, the term shall exclude antagonists of l, a~~, ] jime _ _ : prtilifoiiijmg, : l:)1ih'Yt'Fietbiii'6eMl(***1 and antagonists of those tw~ ( * * * ! Targets which are identified in a sealed and dated envelope provided by CAT to the ft,~&'Offii!.iit'fM!i!iWW8t1P8E1eij(***1 on or before the Effective Date . The London office of Arnold & Porter shall keep such envelope in a safe and secure manner until such time as instructed in a written document signed by both Parties to open such envelope or to release such envelope as may be directed in such document