definiens: shall mean an Antigen with respect to which, at the time such Antigenis first identified by ABX as provided in Section 2.2.1(a ) or first proposed by AZ for consideration as a ProposedAntigen pursuant to Section 2.2.1(a ), whichever is earlier, ( a ) ABX has granted to a Third Party under an ExistingCollaboration, without breach of the exclusivity provisions of Article 17, a license or other right to antibodies theretothat would preclude ABX from granting AZ an exclusive license to Exploit Antibodies that bind to and are directedagainst such Antigen under this Agreement ; ( b ) the terms and conditions of any ABX In - License as in effect as of[Confidential treatment requested ], prohibit ABX from granting a license or other rights under Licensed ABX IP Rights;or ( c ) [ Confidential treatment requested ]