Patent ID: 7259247

Claim:
A mouse monoclonal antibody that recognizes a human 8F4 polypeptide, wherein said 8F4 polypeptide: a) is an inducible T cell costimulatory molecule; b) occurs on two-signal-activated human CD4 + T lymphocytes from human peripheral blood; c) exhibits a molecular weight of about 55 to 60 kilodaltons as determined by non-reducing sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE); and d) is a dimer of two peptide chains exhibiting molecular weights of about 27 kilodaltons and 29 kilodaltons, as measured by reducing SDS-PAGE, wherein the human 8F4 polypeptide is recognized by the antibody produced by the hybridoma deposited with the Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (“DSMZ”) and assigned accession no. DSM ACC2539; and wherein the mouse monoclonal antibody, in conjunction with anti-CD3 monoclonal antibody OKT3, costimulates proliferation of human T lymphocytes.